How Health Insurance Works in the USA: 2026 Guide to Plans

Health insurance card, stethoscope and calculator on a desk next to a plan comparison sheet

Last reviewed: October 1, 2026

Short answer: Private health insurance in the USA is a contract: you pay a monthly premium, and the plan pays part of your medical bills after you pay your share through a deductible, copays and coinsurance, up to a yearly out-of-pocket maximum. Many people get a plan through an employer. People without job-based coverage can buy one through the Health Insurance Marketplace (HealthCare.gov or a state Marketplace), where income-based premium tax credits may lower the price. Medicaid and CHIP cover people with low incomes, and Medicare covers people 65 or older.

You can usually enroll only during an open enrollment period or within a limited window after a qualifying life event such as losing coverage, moving, marrying or having a baby. Compare plans on total yearly cost, not premium alone.

This guide explains the vocabulary, plan types, enrollment rules and costs, with two fictional worked examples. It draws on HealthCare.gov, CMS, Medicare.gov, Medicaid.gov, the US Department of Labor, the IRS, USA.gov and the NAIC. We do not recommend any insurer or plan, and we do not show real premiums.

This article is general information, not financial, insurance, tax or medical advice. Rules differ by state, plan and plan year, so confirm every figure for your own plan year on the official pages listed at the end.

In this guide

Where Americans get health coverage
The vocabulary: premium, deductible, copay and more
A worked example: one person's year of care
Plan types: HMO, PPO, EPO, POS and HDHP
Metal tiers: Bronze, Silver, Gold, Platinum
ACA basics: what every comprehensive plan must do
Employer coverage and open enrollment
COBRA: keeping a job-based plan after you leave
The Marketplace: dates and special enrollment
Premium tax credits and cost-sharing reductions
Medicaid and CHIP basics
Medicare in brief
HSA, FSA and HRA compared
Short-term plans, sharing ministries and fixed indemnity
International students, immigrants and visitors
How to choose a plan, step by step
Using your insurance
Surprise billing protections and good faith estimates
Appeals and external review
Dental and vision coverage
Tax forms, reconciling the credit and the self-employed deduction
Scams and unauthorized plan switching
Where to get free help
Common mistakes to avoid
Checklist before you enroll
FAQ
Bottom line
Sources

Where Americans get health coverage

There is no single national health system in the United States. Coverage comes from a mix of private plans and public programs, and which one you use depends mainly on your job, age, income and immigration status.

Source of coverage	Who it is for	When you can enroll
Employer (group) plan	Employees and usually their spouse and children	When hired, at the employer's yearly open enrollment, or after a qualifying life event
Marketplace (individual) plan	People without job-based coverage: self-employed, part-time workers, early retirees, some newcomers	Open Enrollment (November 1 to January 15 on HealthCare.gov) or a Special Enrollment Period
COBRA continuation	People who lose a job-based plan	Within the election window after coverage ends
Medicaid and CHIP	People and families with low incomes, children, pregnant women, some people with disabilities	Any time of year
Medicare	People 65 or older, and some younger people with a disability, End-Stage Renal Disease or ALS	Around your 65th birthday and at set yearly periods
Student health plan	College and university students	At the start of the academic term

The vocabulary: premium, deductible, copay and more

Every US health plan splits costs between you and the insurer using the same handful of terms.

Term	What it means	What to watch
Premium	The amount you pay each month to keep the plan active, whether or not you use care.	It does not count toward your deductible or out-of-pocket maximum.
Deductible	The amount you pay for covered services each year before the plan starts sharing most costs.	Preventive care is covered before the deductible.
Copay (copayment)	A fixed dollar amount you pay for a service, such as a doctor visit or a prescription.	Copays may not count toward the deductible.
Coinsurance	A percentage of the cost you pay after meeting the deductible, for example 20%.	It applies to the plan's allowed amount, not the list price.
Out-of-pocket maximum	HealthCare.gov defines it as the most you have to pay for covered services in a plan year. After you reach it through deductibles, copayments and coinsurance for in-network care, the plan pays 100% of covered benefits.	It excludes premiums and services the plan does not cover.
Network	The doctors, hospitals and pharmacies that have a contract with your plan.	Out-of-network care costs more or is not covered.
Formulary	HealthCare.gov defines it as a list of prescription drugs covered by a plan, also called a drug list.	Drugs sit in cost tiers.
Prior authorization	Approval from the health plan that may be required before you get a service or fill a prescription for it to be covered.	Usually requested by your doctor's office.
Explanation of benefits (EOB)	A statement from the insurer showing what a provider charged, what the plan paid and what you may owe.	An EOB is not a bill.

Federal rules cap the out-of-pocket maximum for Marketplace plans. HealthCare.gov lists the limit as $10,600 for an individual and $21,200 for a family for the 2026 plan year, and $12,000 for an individual and $24,000 for a family for the 2027 plan year. Many plans set a lower figure.

One more term matters: the allowed amount. This is the price the plan has negotiated with an in-network provider. It is often far below the list price, and your deductible and coinsurance are calculated on it.

A worked example: one person's year of care

The quickest way to understand cost sharing is to follow one person through a year. The example below is fictional and illustrative only. Every name and price is invented.

The plan. Maya has a fictional plan with a $420 monthly premium, a $2,000 deductible, 20% coinsurance after the deductible and a $6,500 out-of-pocket maximum. Primary care visits cost a $30 copay and generic drugs a $10 copay. In this plan, copays do not reduce the deductible, but they do count toward the out-of-pocket maximum.

Month	Care (all in network)	Allowed amount	Maya pays	Why
January	Annual preventive checkup	Not relevant	$0	Preventive care is covered without cost sharing in network
March	Two primary care visits	Not relevant	$60	2 x $30 copay
May	MRI scan	$1,200	$1,200	All of it goes to the deductible; $800 of deductible remains
August	Outpatient surgery	$9,000	$2,440	$800 to finish the deductible, then 20% of the remaining $8,200 = $1,640
All year	12 generic prescription fills	Not relevant	$120	12 x $10 copay
Total out-of-pocket for care			$3,820	$60 + $1,200 + $2,440 + $120

The full yearly cost. Maya's premiums total $420 x 12 = $5,040. Add $3,820 in out-of-pocket costs and her year costs $8,860.

What if something else happened? Suppose Maya also needed a hospital stay in November with an allowed amount of $20,000. Her 20% share would be $4,000. But she is only $6,500 - $3,820 = $2,680 away from her out-of-pocket maximum, so she pays $2,680 and the plan pays the other $17,320. Her worst-case year is therefore $5,040 in premiums plus $6,500, or $11,540.

Plan types: HMO, PPO, EPO, POS and HDHP

The plan type tells you how freely you can pick doctors and whether you need a referral to see a specialist. It does not tell you how generous the plan is. HealthCare.gov describes four network designs, and a fifth label, HDHP, describes the deductible and can be combined with any of them.

Type	How it works	Out-of-network care
HMO (Health Maintenance Organization)	Usually limits coverage to care from doctors who work for or contract with the HMO. Many HMOs ask you to pick a primary care doctor who refers you to specialists.	Generally not covered except in an emergency
PPO (Preferred Provider Organization)	You pay less if you use providers in the plan's network, and you can usually see specialists without a referral.	Covered, but at a higher cost to you
EPO (Exclusive Provider Organization)	A managed care plan where services are covered only if you use doctors, specialists or hospitals in the network.	Not covered except in an emergency
POS (Point of Service)	You pay less if you use network providers. These plans often require a referral from your primary care doctor to see a specialist.	Covered at a higher cost, often with a referral
HDHP (High Deductible Health Plan)	A plan with a lower monthly premium and a higher deductible, designed to work with a Health Savings Account (HSA).	Depends on the network type

Rules vary by insurer, so read the plan documents for the actual referral and out-of-network rules.

Metal tiers: Bronze, Silver, Gold, Platinum

Metal tiers describe how you and the plan split costs on average. They say nothing about quality of care. HealthCare.gov lists four categories, plus Catastrophic plans for a limited group.

Category	Plan pays (average)	You pay (average)	Deductible level
Bronze	60%	40%	High
Silver	70%	30%	Moderate
Silver with cost-sharing reductions	73% to 96%	6% to 27%	Low
Gold	80%	20%	Low
Platinum	90%	10%	Low

These are averages across a typical population, not what you personally will pay.

Catastrophic plans are a fifth category available to people under 30 and to people who qualify for a hardship or affordability exemption. HealthCare.gov describes them as having low monthly premiums and very high deductibles. They cover the essential health benefits and at least three primary care visits a year before the deductible. If you qualify for a premium tax credit or cost-sharing reductions, HealthCare.gov notes that a Bronze or Silver plan may be a better value.

ACA basics: what every comprehensive plan must do

The Affordable Care Act (ACA) sets minimum standards for comprehensive health plans. Four protections matter most.

Essential health benefits

HealthCare.gov lists ten categories all Marketplace plans must cover: outpatient care; emergency services; hospitalization; pregnancy, maternity and newborn care; mental health and substance use disorder services; prescription drugs; rehabilitative and habilitative services and devices; laboratory services; preventive and wellness services and chronic disease management; and pediatric services, including oral and vision care for children.

Preventive care at no cost

Most plans must cover a set of preventive services, such as screening tests and immunizations, without a copayment or coinsurance, even if you have not met your deductible. The condition is that you use an in-network provider. Ask when you book whether the visit will be billed as preventive.

Pre-existing conditions

Marketplace plans cannot reject you, charge you more or refuse to pay for essential health benefits because of a condition you had before coverage started. Pregnancy is covered from the day the plan starts. The exception is a grandfathered individual plan bought on or before March 23, 2010.

Dependents to age 26

Young adults can generally stay on a parent's plan until they turn 26. For job-based plans this applies even if the young adult is married, not in school or not a tax dependent. On a Marketplace plan, coverage can continue through December 31 of the year the person turns 26.

Employer coverage and open enrollment

Job-based coverage is a group plan that your employer chooses and usually helps pay for. You can normally join when you are hired, during the employer's yearly open enrollment, or after a qualifying life event.

Open enrollment is your yearly chance. If you miss the employer's dates, you usually wait a year unless you have a qualifying life event. Compare the plans offered using yearly premiums from your paycheck plus likely out-of-pocket costs.

Can you choose a Marketplace plan instead?

You can, but you will probably not get financial help. HealthCare.gov explains that if you switch to a Marketplace plan, the employer will not pay part of your premium, and you generally cannot get a premium tax credit if the job-based offer is considered affordable and meets the minimum value standard. A plan meets minimum value if it is designed to cover at least 60% of medical costs and gives substantial hospital and doctor coverage. The IRS sets the affordability percentage each year; its premium tax credit questions and answers list 9.96% of household income for 2026.

COBRA: keeping a job-based plan after you leave

COBRA is a federal law that lets workers and their families keep their group health plan for a limited time after job loss, reduced hours, divorce, death and certain other events. You usually pay the whole premium yourself.

The main rules from the US Department of Labor:

Which employers. COBRA generally applies to group health plans sponsored by employers with 20 or more employees in the prior year.
How long. Coverage usually lasts up to 18 months, and up to 36 months for certain qualifying events.
Election window. You have 60 days to elect COBRA, counted from the later of the date coverage ends or the date you receive the election notice.
Cost. You may be required to pay the entire premium, up to 102% of the cost to the plan.
Family members. Spouses and children can elect COBRA independently, even if the former employee does not.

COBRA or a Marketplace plan?

Losing job-based coverage also gives you a 60-day Special Enrollment Period on the Marketplace, and HealthCare.gov notes that a Marketplace plan may cost less than COBRA, especially if you qualify for savings based on income.

One trap: if you elect COBRA and later stop paying or cancel it yourself, that voluntary end does not open a Special Enrollment Period.

The Marketplace: dates and special enrollment

The Health Insurance Marketplace is where individuals and families buy ACA-compliant private plans and apply for financial help. HealthCare.gov serves most states; some states run their own.

Open Enrollment dates as published

For 2027 coverage, HealthCare.gov publishes these dates:

November 1: Open Enrollment starts.
December 15: the last day to enroll or change plans for coverage that starts January 1.
January 15: Open Enrollment ends. Plans chosen from December 16 through January 15 start February 1.

State Marketplaces may use different dates, so confirm the deadline for your state and plan year.

Special Enrollment Periods

Outside Open Enrollment, you can enroll only if you have a qualifying life event. In most cases you have 60 days from the event to pick a plan. HealthCare.gov lists these main events:

Loss of health coverage: losing a job-based plan, COBRA running out, losing a student plan, aging off a parent's plan at 26, or losing Medicaid or CHIP (a 90-day window applies to Medicaid and CHIP loss).
Household changes: marriage, birth, adoption or foster placement, or divorce or death that causes a loss of coverage.
Changes in residence: moving to a new ZIP code or county, moving to the US from another country, or moving to or from school.
Other events: gaining citizenship or lawful presence, leaving incarceration, or being offered an individual coverage HRA or QSEHRA by an employer.

You may be asked for documents proving the event, such as a letter showing the date coverage ended.

Premium tax credits and cost-sharing reductions

Two kinds of financial help exist on the Marketplace: the premium tax credit lowers your monthly premium, and cost-sharing reductions lower your deductible and copays on Silver plans. Both depend on your household income and size. The rules changed recently, so confirm them for your plan year.

The premium tax credit

HealthCare.gov describes the premium tax credit as a tax credit you can use to lower your monthly insurance payment. The amount is based on the household size and the estimated income you put on your application. You can have it paid in advance directly to your insurer.

The IRS lists the main conditions. You must be enrolled in a Marketplace plan, not be able to get affordable employer coverage that meets minimum value, not be eligible for programs such as Medicaid, Medicare, CHIP or TRICARE, not be claimed as a dependent, and generally not file as married filing separately.

On income, the IRS explains that for tax years 2021 through 2025 Congress temporarily removed the rule that household income may not be more than 400% of the federal poverty line. In its current questions and answers, the IRS describes eligibility as household income of at least 100% and not more than 400% of the federal poverty line. HealthCare.gov publishes 2027 income levels from November 1.

Why your income estimate matters more now

If you take more advance credit than your final income allows, you repay the difference when you file your federal tax return. The IRS states that for tax years after 2025 there is no repayment cap: you must repay the full amount by which your advance payments exceed your credit. So estimate income carefully and report changes to the Marketplace promptly.

Cost-sharing reductions

Cost-sharing reductions (CSRs) are extra savings that lower your deductible, copayments, coinsurance and out-of-pocket maximum. You must pick a Silver plan to get them. If you qualify and choose Bronze or Gold instead, you keep your premium tax credit but lose the extra savings. The lower your income within the qualifying range, the more you save. Catastrophic plans do not qualify.

Medicaid and CHIP basics

Medicaid and the Children's Health Insurance Program (CHIP) provide free or low-cost coverage to people with low incomes, and you can apply at any time of year. Each state runs its own program within federal rules, so eligibility differs by state.

Who is covered. Medicaid.gov lists children, pregnant women, parents, seniors and individuals with disabilities. The ACA gave states the option to extend eligibility to adults with income at or below 133% of the federal poverty level, and most states have done so. Federal law requires every state to cover children to at least 133% of the federal poverty level, and most states go higher, often through CHIP.
How to apply. Fill out a Marketplace application, which passes your information to the state agency if you appear eligible, or apply directly to your state Medicaid agency.
Retroactive coverage. Medicaid.gov states that benefits may also be covered retroactively for up to three months before the month of application if you would have been eligible then.

If you are eligible for Medicaid, you generally cannot get a premium tax credit for a Marketplace plan.

Medicare in brief

Medicare is federal health insurance for people 65 or older who meet citizenship or residency requirements, and for some younger people with a disability. It is separate from the Marketplace.

Part A (hospital insurance) covers inpatient hospital care, skilled nursing facility care and hospice.
Part B (medical insurance) covers doctors' services, outpatient care and preventive services.
Part C (Medicare Advantage) is a private-plan alternative that bundles Parts A and B and usually Part D.
Part D helps cover prescription drugs through private plans that follow Medicare rules.
Medigap is private supplemental insurance for out-of-pocket costs in Original Medicare.

Your Initial Enrollment Period lasts seven months: it starts three months before the month you turn 65 and ends three months after. Medicare.gov warns that if you miss it, you may have to wait to sign up and pay a monthly late enrollment penalty for as long as you have Part B, unless you qualify for a special period.

Once you have Medicare, the Marketplace is no longer for you. HealthCare.gov states that it is against the law for someone who knows you have Medicare to sell you a Marketplace plan, and Marketplace coverage does not end automatically when Medicare starts.

HSA, FSA and HRA compared

HSAs, FSAs and HRAs are tax-advantaged accounts for medical costs your plan does not pay. They differ in who owns the money, who contributes and whether unused funds roll over.

Feature	HSA (Health Savings Account)	Health FSA (Flexible Spending Arrangement)	HRA (Health Reimbursement Arrangement)
Who owns it	You. It stays with you if you change jobs.	Set up by the employer; generally tied to the job	The employer
Who contributes	You, your employer or both	Mainly you, by salary reduction; the employer may add	Employer only
Plan required	An HSA-eligible HDHP, with no other disqualifying coverage	Offered through an employer; cannot be used with a Marketplace plan	Depends on the HRA type
Published limits	2026: $4,400 self-only, $8,750 family. 2027: $4,500 self-only, $9,000 family. Extra $1,000 catch-up at age 55 or older.	2026: $3,400 salary reduction limit	Set by the employer, within the rules for the HRA type
Unused money	Rolls over every year	Generally lost at year end, unless the employer offers a grace period of up to 2.5 months or a carryover (up to $680 from 2026 plan years)	Employer decides whether it carries over

What makes a plan HSA-eligible

To contribute to an HSA, you must be covered by a qualifying HDHP. HealthCare.gov lists these thresholds:

2026: minimum deductible of $1,700 self-only or $3,400 family; out-of-pocket maximum of no more than $8,500 self-only or $17,000 family.
2027: minimum deductible of $1,750 self-only or $3,500 family; out-of-pocket maximum of no more than $8,700 self-only or $17,400 family.

HealthCare.gov also states that all Bronze and Catastrophic Marketplace plans now work with HSAs, and that other plans may be eligible.

HRAs you buy your own plan with

Some employers fund an individual coverage HRA or a QSEHRA that reimburses premiums for a plan you buy yourself. Being newly offered one of these opens a Special Enrollment Period on the Marketplace. The offer can affect premium tax credit eligibility, so report it on your Marketplace application.

Short-term plans, sharing ministries and fixed indemnity

Several products look like health insurance and cost less, but they are not comprehensive coverage, do not have to follow the ACA protections above and can leave you with very large bills.

Product	What it is	Main limits
Short-term, limited-duration insurance	Temporary coverage sold outside the Marketplace	CMS states it is not subject to the rules against discrimination based on health status, pre-existing condition exclusions or annual and lifetime limits. The NAIC adds that these plans may deny you or charge more for a pre-existing condition.
Health care sharing ministry	Members pay a monthly amount and ask the ministry to share their medical costs	The NAIC warns that the ministry is not legally obligated to pay members' health care costs and is generally not regulated by state insurance departments.
Fixed indemnity and hospital indemnity	Pays a fixed cash amount per day or per event, regardless of the actual bill	CMS notes it has traditionally worked as income replacement, not as comprehensive medical coverage.

Federal rules on how long short-term plans may last have shifted. A 2024 federal rule limited new short-term policies to three months, or four with renewals. In August 2025, the Departments of Labor, Health and Human Services and the Treasury said they intend to reconsider that definition and do not intend to prioritize enforcement in the meantime. State law may be stricter. Ask your state insurance department what applies.

CMS also lists short-term plans, health care sharing ministries and fixed indemnity plans among the coverage types the No Surprises Act does not cover.

International students, immigrants and visitors

Newcomers can often buy private coverage, but the options depend on immigration status and length of stay.

Lawfully present immigrants

US citizens, US nationals and lawfully present immigrants can get coverage through the Marketplace. HealthCare.gov's list includes lawful permanent residents (green card holders), refugees and asylees, people with Temporary Protected Status, Cuban and Haitian entrants, Compact of Free Association (COFA) migrants and people with valid non-immigrant visas. Undocumented immigrants cannot get Marketplace coverage.

Financial help is narrower. HealthCare.gov states that starting January 1, 2027, only lawful permanent residents, Cuban and Haitian entrants and COFA migrants can get premium tax credits and cost-sharing reductions; other lawfully present immigrants can still buy a Marketplace plan at full price. For Medicaid and CHIP, many qualified non-citizens face a five-year waiting period, although some states cover lawfully residing children and pregnant women sooner. Check the current HealthCare.gov pages for your status.

International students

Most international students use the health plan arranged by their college or university, and many schools require it or proof of comparable coverage. Before waiving a school plan for a cheaper policy, compare deductibles, exclusions and coverage away from campus.

Exchange visitor sponsors may set their own insurance requirements. Because students on valid non-immigrant visas count as lawfully present, a Marketplace plan may be possible, but usually without financial help under the rule above. For the wider budget, see our guides on how to pay for studying abroad and on opening a student bank account abroad.

Short-term visitors

Tourists and short-stay business visitors generally do not use the US domestic insurance system. They usually rely on travel medical insurance bought before the trip. Our guide to what travel insurance covers and what it does not explains how to read those policies. It is not a substitute for a comprehensive plan if you live in the US.

How to choose a plan, step by step

Choose the plan with the lowest expected total cost for the care you are likely to need, among plans that include your doctors and medicines and that you could afford in a bad year.

Find out which door you are using. Employer plan, Marketplace, Medicaid or CHIP, Medicare or a student plan.
Estimate your care. List prescriptions, planned procedures and specialist visits.
Check the network. Search each plan's provider directory for your doctors, your nearest hospital and your pharmacy.
Check the formulary. Look up each medicine and note its tier and whether prior authorization is required.
Calculate the total yearly cost. Add 12 months of premiums (after any tax credit) to your expected out-of-pocket costs.
Look at the worst case. Premiums plus the out-of-pocket maximum is the most a covered, in-network year can cost. Could you pay it?
Consider the extras. If you qualify for cost-sharing reductions, compare Silver plans first. If you want an HSA, check that the plan is HSA-eligible.
Read the Summary of Benefits and Coverage. It shows costs and exclusions in the same format for every plan.

A fictional two-plan comparison

The following example is illustrative only. Both plans and all prices are invented. Assume all care is in network and subject to the deductible, then coinsurance.

	Plan A (low premium)	Plan B (high premium)
Monthly premium	$310	$470
Yearly premiums	$3,720	$5,640
Deductible	$7,000	$1,500
Coinsurance after deductible	40%	20%
Out-of-pocket maximum	$9,000	$6,000
Healthy year: $500 of care	$3,720 + $500 = $4,220	$5,640 + $500 = $6,140
Moderate year: $5,000 of care	$3,720 + $5,000 = $8,720	$1,500 + 20% of $3,500 ($700) = $2,200; $5,640 + $2,200 = $7,840
Bad year: $40,000 of care	Capped at $9,000; $3,720 + $9,000 = $12,720	Capped at $6,000; $5,640 + $6,000 = $11,640

Plan A costs $1,920 less in premiums each year. In a moderate year, Plan B is $880 cheaper overall, and in a bad year it is $1,080 cheaper. The break-even point is about $3,900 of care: below that, Plan A costs less in total; above it, Plan B does.

Neither plan is better in general. Run the same three scenarios with the real plans in front of you.

Using your insurance

Using a plan by its rules is what keeps bills low. Four habits matter most.

Stay in network

Before any non-emergency appointment, confirm that the doctor, the facility and the lab are in your plan's network.

Get referrals and prior authorization

If your plan requires a referral from your primary care doctor, get it before you see the specialist. If a service or drug needs prior authorization, ask your doctor's office to request it and get the approval reference before the service. HealthCare.gov's internal appeals page says a plan must decide a prior authorization request within 15 days, or within 72 hours in urgent cases.

Know the emergency rules

In a true emergency, go straight to the nearest hospital. HealthCare.gov states that insurers cannot require prior approval for emergency room services or charge you higher copayments or coinsurance because the hospital is out of network. You still owe your plan's normal deductible and cost sharing.

Match the EOB to the bill

After care, your insurer sends an explanation of benefits. It is not a bill. Wait for the provider's bill and compare the two. If the bill is higher than the EOB figure, call the provider's billing office, then the insurer.

If you cannot pay a correct bill at once, ask the provider about a payment plan before using a high-interest card; unpaid medical debt in collections can affect your credit score.

Surprise billing protections and good faith estimates

The No Surprises Act, in effect since January 1, 2022, protects most insured people from unexpected out-of-network bills when they could not choose the provider.

You are protected from out-of-network balance bills for:

Emergency care. The hospital and the providers treating you cannot charge more than your in-network cost-sharing amount, including for post-stabilization services.
Out-of-network providers at an in-network facility. If you go to an in-network hospital, hospital outpatient department or ambulatory surgical center, you keep the protection even if an individual provider there is out of network.
Air ambulance services from out-of-network providers.

Two limits are worth knowing. First, CMS states that ground ambulance services are not covered by the No Surprises Act protections, although some states have their own rules. Second, a provider may ask you to sign a notice and consent form giving up the protections for some non-emergency care. Signing means agreeing to out-of-network rates.

Good faith estimates if you are uninsured or paying yourself

If you do not have insurance or choose not to use it, providers must give you a good faith estimate of expected charges when you schedule care at least three business days in advance, or when you ask for one. If a provider's bill is at least $400 more than its estimate, you can dispute the bill, and you must start the dispute within 120 days of getting the initial bill. Each estimate covers one provider or facility, so for surgery ask each provider separately.

For questions or complaints, CMS runs the No Surprises Help Desk at 1-800-985-3059.

Appeals and external review

If your plan refuses to pay a claim or ends your coverage, you have the right to appeal, first to the insurer and then to an independent reviewer.

Step 1: internal appeal

An internal appeal asks the insurer to conduct a full and fair review of its decision. According to HealthCare.gov:

You must file within 180 days (six months) of receiving notice that the claim was denied.
The insurer must decide within 30 days if the appeal is about a service you have not yet received, and within 60 days if it is about a service you already received.
In urgent situations the process must be sped up.

Keep the denial letter, a copy of your appeal, your doctor's supporting records and notes of every call.

Step 2: external review

If the internal appeal fails, you can ask for an external review by an independent third party. Key rules:

File a written request within four months after the date you receive the notice or final determination.
External review is available for denials involving medical judgment, experimental-treatment decisions and cancellations for alleged false information.
Standard reviews are decided within 45 days. Expedited reviews are decided within 72 hours or less, depending on medical urgency.
There is no charge under the federal HHS-administered process; under other processes the charge cannot exceed $25.
The insurer is required by law to accept the external reviewer's decision.

Your state insurance department or consumer assistance program can help you file.

Dental and vision coverage

For adults, dental and vision care are usually separate from medical insurance. For children, they are part of the essential health benefits.

Children. Pediatric oral and vision care are essential health benefits. HealthCare.gov explains that dental coverage for children 18 and under must be available to you, either inside a health plan or as a stand-alone plan, although you are not required to buy it.
Adults. Dental coverage is not an essential health benefit for adults, so insurers do not have to offer it.
Stand-alone dental plans on the Marketplace. You pay a separate premium, and you cannot buy a Marketplace dental plan unless you are buying a health plan at the same time. Stand-alone plans may have waiting periods for adult services.
Employer plans. Many employers offer separate dental and vision plans with their own premiums, annual limits and networks.

Dental and vision plans work differently from medical plans. They often cap what the plan pays in a year, which is the opposite of an out-of-pocket maximum. Read the annual maximum and waiting periods before you buy.

Tax forms, reconciling the credit and the self-employed deduction

Health coverage affects your federal tax return through the 1095 forms, the reconciliation of any advance premium tax credit and, for self-employed people, a possible premium deduction.

Forms 1095-A, 1095-B and 1095-C

Form	Who sends it	What it shows
1095-A	The Marketplace	Months of coverage, premiums and advance credit payments
1095-B	Health insurance providers	Who was covered and when
1095-C	Certain employers	What coverage the employer offered

Wait for Form 1095-A before filing; you can file without the other two. Do not attach any of them to your return.

Reconciling the premium tax credit

If advance payments of the premium tax credit were paid to your insurer, you must file a federal return with Form 8962. The form compares the advance payments with the credit you actually qualify for based on your final income. If you were paid too much, you repay the excess.

The IRS warns that not reconciling delays your refund and can cost you advance payments in future years.

The self-employed health insurance deduction

If you are self-employed with a net profit, you may be able to deduct premiums you paid for medical, dental and vision insurance for yourself, your spouse, your dependents and your children under 27. The IRS instructions for Form 7206 set two limits: the deduction cannot be more than the net profit from the business under which the plan is established, and you cannot take it for any month in which you were eligible to participate in a health plan subsidized by your employer or your spouse's employer.

If you also receive a premium tax credit, the two calculations interact, so many people use a tax professional. Marketplace savings are based on estimated net income for the coverage year; if your earnings are irregular, as in our guide on getting paid as a freelancer by international clients, update your estimate during the year.

Scams and unauthorized plan switching

Health insurance fraud usually means fake Marketplace websites, limited products sold as full coverage, or agents who enroll or switch people without consent.

Fake Marketplace sites and ads

HealthCare.gov advises getting information only from official government websites, checking for a .gov address, and being cautious about health insurance promotions on social media.

Unauthorized enrollment and plan switching

CMS has reported cases where agents or brokers changed consumers' federal Marketplace enrollments to a different plan without their informed consent. Since July 2024, CMS has blocked agents and brokers from changing an enrollment unless they are already associated with it; working with a new agent requires a three-way call with the Marketplace Call Center.

If you think you were enrolled or switched without consent, call the Marketplace Call Center at 1-800-318-2596 (TTY 1-855-889-4325) promptly so the coverage issue can be resolved.

Protecting yourself

Do not give your Social Security number, bank details or health information to an unsolicited caller.
Nobody legitimate will ask for payment to apply for coverage or to keep it. The Marketplace will never threaten you or ask for payment to keep coverage.
Verify that an agent and the insurance company are licensed with your state insurance department, as the NAIC recommends.
Report fraud to the FTC at reportfraud.ftc.gov and to the Marketplace Call Center.

See also our guide on how to avoid loan scams and fake offers.

Where to get free help

You should never pay for enrollment help. These sources are free to use.

Assisters and navigators. HealthCare.gov describes assisters as trained and certified by the Marketplace to help you apply and enroll. They give impartial information, can help with Medicaid and CHIP applications, and their service is free. Find them at localhelp.healthcare.gov.
Agents and brokers. Licensed agents registered with the Marketplace can also help you enroll. They are generally paid by the insurance companies whose plans they sell, not by you, and they may not represent every insurer.
The Marketplace Call Center. 1-800-318-2596, available all day, every day.
Your state insurance department. It licenses insurers and agents and handles complaints.

Common mistakes to avoid

Most costly mistakes involve deadlines, networks and misunderstanding what a product is.

Choosing on premium alone. The cheapest premium can be the most expensive plan in a year when you need care. Compare total yearly cost.
Missing the enrollment window. Outside Open Enrollment you need a qualifying life event, and most windows are 60 days.
Dropping COBRA voluntarily mid-year. That does not open a Special Enrollment Period.
Assuming your doctor is in network. Check every year. Networks change even when the plan name does not.
Qualifying for cost-sharing reductions and not picking Silver. The extra savings apply only to Silver plans.
Underestimating income. With no repayment cap after 2025, excess advance credit must be repaid in full at tax time.
Letting a plan auto-renew without looking. The NAIC recommends reviewing plans every year.
Missing Medicare's Initial Enrollment Period. Late penalties can last as long as you have Part B.

Checklist before you enroll

I know which route applies to me.
I know my enrollment deadline and when coverage would start.
I have confirmed the plan is comprehensive, ACA-compliant coverage.
I have checked that my doctors, hospital and pharmacy are in network.
I have looked up each of my prescriptions on the formulary.
I know the premium, deductible, copays, coinsurance and out-of-pocket maximum.
I have calculated total yearly cost for a healthy year, a moderate year and a bad year.
I have checked whether I qualify for a premium tax credit, cost-sharing reductions, Medicaid or CHIP.
My income estimate is realistic.
I enrolled through an official site, my employer or a verified licensed agent.
I saved my plan documents and paid the first premium on time.

FAQ

How does health insurance work in the USA in simple terms?

You pay a monthly premium to keep the plan. When you get care, you pay your share through a deductible, copays and coinsurance, and the plan pays the rest. Once your share reaches the out-of-pocket maximum for the year, the plan pays 100% of covered in-network care.

What is the difference between a deductible and an out-of-pocket maximum?

The deductible is what you pay before the plan starts sharing most costs. The out-of-pocket maximum is the most you pay in a plan year for covered in-network care, counting the deductible, copays and coinsurance. Premiums count toward neither.

When is open enrollment for health insurance?

On HealthCare.gov, Open Enrollment for 2027 coverage is published as November 1 through January 15, with a December 15 deadline for coverage starting January 1. State Marketplaces can set different dates. Employer plans set their own dates.

Can I get health insurance outside open enrollment?

Yes, if you have a qualifying life event such as losing other coverage, getting married, having or adopting a child, or moving. This opens a Special Enrollment Period, usually 60 days.

How much does health insurance cost per month in the US?

There is no single figure. Premiums depend on location, age, plan category, household size and any employer or tax credit contribution. Preview plans on HealthCare.gov or your state Marketplace to see your price.

Do I qualify for a subsidy on the Marketplace?

It depends on household income and size, any offer of affordable employer coverage, tax filing status and immigration status. The IRS currently describes the income range as 100% to 400% of the federal poverty line.

Can international students get health insurance in the USA?

Yes. Most use their school's student health plan, and many schools require it or comparable coverage. Students with valid non-immigrant visas are treated as lawfully present and may be able to buy a Marketplace plan, though HealthCare.gov states that from January 1, 2027 premium tax credits are limited to certain immigration statuses.

Can immigrants buy Marketplace health insurance?

Lawfully present immigrants can buy Marketplace coverage. Undocumented immigrants cannot, although they can apply for eligible family members. Financial help and Medicaid depend on your specific status.

Can I use an HSA with any health plan?

No. You need an HSA-eligible high deductible health plan that meets the IRS minimum deductible and maximum out-of-pocket limits for the year. HealthCare.gov states that all Bronze and Catastrophic Marketplace plans now work with HSAs, and others may qualify. Check the plan's HSA-eligible label.

Are short-term health plans real insurance?

They are insurance, but not comprehensive coverage. They do not have to cover the essential health benefits or pre-existing conditions and may have annual or lifetime limits.

What should I do if I get a surprise medical bill?

Do not pay it immediately. Compare it with your EOB, ask for an itemized bill, and check whether the No Surprises Act applies. If unresolved, call the No Surprises Help Desk at 1-800-985-3059.

Is health insurance mandatory in the USA?

The IRS refers to the federal health coverage requirement in connection with tax years before 2019. Some states have their own coverage requirements, so check your state's rules.

Bottom line

US health insurance looks complicated because the price is split into pieces. Put the pieces back together and the choice becomes simpler: add the yearly premiums to what you are likely to pay for care, check your worst case against the out-of-pocket maximum, and make sure your doctors and medicines are covered.

Respect the enrollment deadlines, be accurate about your income, and treat anything that is not ACA-compliant as a limited product. When something goes wrong, use the EOB, the No Surprises Act, appeals and free help from navigators.

Limits and subsidy rules change each year, so confirm the figures against the official pages below.

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