How does US health insurance work?

US health insurance is a system where you (and often your employer) pay premiums each month for health coverage. When you need medical care, you pay a portion of the costs through deductibles (the amount you pay before insurance kicks in), copays (fixed fees per visit/prescription), and coinsurance (a percentage you pay after the deductible). The insurer pays the remaining covered costs. Most Americans get insurance through their employer, through the ACA Marketplace (healthcare.gov), or through government programmes (Medicare for 65+, Medicaid for low-income).

What is a deductible in US health insurance?

A deductible is the amount you pay for covered healthcare services before your insurance begins to pay. For example, with a $2,000 deductible, you pay the first $2,000 of covered costs each year yourself. After that, your insurance starts sharing the costs (usually through coinsurance — e.g. you pay 20%, insurer pays 80%). Most preventive care (annual checkups, vaccinations) is covered before the deductible under ACA rules. Family deductibles are higher than individual deductibles.

What is the difference between HMO and PPO?

HMO (Health Maintenance Organisation): Usually lower premiums and lower out-of-pocket costs. Requires you to choose a primary care physician (PCP) who coordinates all care. Referrals needed to see specialists. Little or no coverage for out-of-network providers. Best if you want lower costs and are willing to coordinate care through a PCP. PPO (Preferred Provider Organisation): Higher premiums but more flexibility. See any doctor (in or out of network) without a referral. In-network care costs less; out-of-network care is covered but more expensive. Best for those who want maximum flexibility or have existing specialist relationships.

US Health Insurance Explained -

The Key Terms You Must Know

Before anything else: the US health insurance vocabulary. These terms define how much you actually pay when you use healthcare:

Pay monthly

Premium

The monthly payment for your insurance plan — whether you use healthcare or not. Employer plans often split this cost between you and your employer. ACA marketplace plans offer subsidies based on income. Higher premiums generally mean lower out-of-pocket costs when you use care.

Pay first

Deductible

The amount you pay for covered services before insurance starts paying. If your deductible is $1,500, you pay the first $1,500 of covered healthcare costs each year. After that, insurance shares costs with you. Preventive care is usually exempt — covered before the deductible.

Per visit

Copay

A fixed amount you pay for a specific service — e.g. $20 for a primary care visit, $50 for a specialist, $10 for a generic prescription. Copays often apply even before the deductible is met on some plans, or only after. Check your plan's Summary of Benefits.

After deductible

Coinsurance

After you've met your deductible, you and your insurer split the remaining costs at an agreed percentage. A common split is 80/20 — insurer pays 80%, you pay 20%. If a procedure costs $5,000 and your deductible is already met, you pay $1,000 and the insurer pays $4,000.

Annual cap

Out-of-Pocket Maximum

The most you'll pay in a year for covered services. Once reached, your insurance pays 100% for the rest of the year. In 2025, ACA-compliant plans cap this at $9,450 for individuals and $18,900 for families. This is your financial protection against catastrophic illness.

Critical

Network

The set of doctors, hospitals, and providers that have contracted with your insurer at negotiated rates. In-network care costs significantly less than out-of-network. With an HMO, out-of-network is usually not covered at all. Always confirm a provider is in-network before scheduling non-emergency care.

Plan Types: HMO, PPO, EPO, HDHP

Plan Type	Premiums	Flexibility	PCP Required?	Out-of-Network	Best For
HMO	Lower	Limited	Yes	Not covered	Cost-conscious, simple healthcare needs
PPO	Higher	High	No	Covered (higher cost)	Those needing specialist flexibility
EPO	Moderate	Limited	No	Not covered	Lower cost, no referrals needed
HDHP + HSA	Lowest	Varies	Varies	Varies	Healthy, want to contribute to HSA

HSA: The Triple Tax Advantage

If you have a High Deductible Health Plan (HDHP — defined in 2025 as a deductible of at least $1,650 individual/$3,300 family), you can open a Health Savings Account (HSA). The HSA offers three tax benefits in one:

Contributions are tax-deductible: Reduce your taxable income by the amount you contribute (up to $4,300 individual/$8,550 family in 2025)
Growth is tax-free: Invest HSA funds in index funds or ETFs and pay no tax on gains
Withdrawals for qualified medical expenses are tax-free: Use the money for medical, dental, or vision expenses with no tax owed

After age 65, HSA funds can be withdrawn for any purpose (taxed as ordinary income — like a traditional IRA), making it effectively a stealth retirement account if you stay healthy. Max out your HSA before other retirement accounts if you're on an HDHP.

ACA Marketplace: Coverage if You Don't Have Employer Insurance

The Affordable Care Act (ACA) created healthcare.gov — the federal marketplace where individuals and families without employer coverage can shop for insurance. Key facts:

Open Enrollment runs annually November 1 – January 15. Missing this window means you generally can't enroll until next year unless you have a qualifying life event (job loss, marriage, birth of child, moving states)
Premium Tax Credits (subsidies) are available for households earning 100%–400% of the federal poverty level. Check your eligibility at healthcare.gov
Metal tiers: Bronze (lowest premium, highest deductible), Silver, Gold, Platinum (highest premium, lowest deductible). Choose based on how much healthcare you expect to use
Silver plans and Cost-Sharing Reductions: If your income is below 250% of FPL, you may qualify for cost-sharing reductions that significantly lower deductibles and out-of-pocket costs on Silver plans — making Silver tier potentially more valuable than its premium suggests

✅ Always check subsidy eligibility

Premium Tax Credits dramatically reduce ACA plan costs for most middle-income Americans. A family of four earning up to ~$125,000 may qualify for some subsidy. Check your estimated eligibility at healthcare.gov before assuming you can't afford coverage.

Medicare & Medicaid

Medicare is federal health insurance for Americans 65+, and for some younger people with disabilities. Part A covers hospital care (most people pay no premium), Part B covers outpatient care (~$185/month premium in 2025), and Part D covers prescription drugs. Many people supplement with Medigap (supplemental) policies or choose Medicare Advantage (Part C) which bundles everything through a private insurer.

Medicaid is joint federal-state insurance for low-income individuals and families. Eligibility varies by state — some states expanded Medicaid under the ACA, others didn't. Check your state's specific eligibility at medicaid.gov.

Frequently Asked Questions

The out-of-pocket maximum is the most you'll pay in a single year for covered in-network healthcare services. Once you hit this limit, your insurance pays 100% of covered costs for the rest of the year. In 2025, ACA plans cap the individual out-of-pocket maximum at $9,450 and family at $18,900. Employer plans may have different limits. This is your most important financial protection — without it, a single major illness could cost an unlimited amount.

Not necessarily — it depends on whether your doctor is in-network on your new plan. Before switching plans during open enrollment, check whether your primary care physician, any specialists you see regularly, and your preferred hospitals are in-network on the new plan. The insurer's website should have a provider directory. Out-of-network care can cost dramatically more, or may not be covered at all on HMO and EPO plans.

If you miss the November–January open enrollment window, you generally cannot get ACA marketplace coverage until the following November — unless you have a qualifying life event (Special Enrollment Period or SEP). Qualifying events include: losing other health coverage (job loss, aging off parents' plan at 26), getting married or divorced, having a baby or adopting, moving to a new area, and certain other life changes. You typically have 60 days from the qualifying event to enroll.

Important: US healthcare rules, plan options, premiums, deductibles, and eligibility thresholds change annually. Figures shown are 2025 guidance — always verify current details at healthcare.gov or with your employer benefits administrator. Not regulated insurance advice.