Key Takeaways
Start here
Why Health Insurance Exists
Next
The Core Costs You'll See on Every Plan
Then
Plan Types: HMO, PPO, EPO, and HDHP
When you're ready
How to Get Coverage
Before you enroll
Networks, Prior Authorization, and Other Things That Trip People Up
Why Health Insurance Exists
Medical care in the United States is expensive. A single emergency room visit can cost thousands of dollars before any treatment begins. Health insurance exists to prevent those costs from becoming financially catastrophic by pooling risk across a large group of people — everyone pays a predictable amount, and the pool covers whoever faces large bills.
In exchange for monthly payments called premiums, your insurer agrees to share covered medical costs according to the terms of your policy. This article is general educational information — not personalized financial or medical advice. For decisions about your own coverage, consult a licensed insurance agent or a qualified adviser.
If terms like deductible or coinsurance already feel unfamiliar, our plain-English glossary of health insurance terms is a useful companion to this overview.
The Core Costs You'll See on Every Plan
Understanding a health plan means understanding four basic cost layers that work together:
Premium
The fixed monthly amount you pay to maintain your health insurance coverage, whether or not you use any medical services.
Deductible
The amount you must pay out of pocket for covered care each plan year before your insurer begins sharing costs.
Copay
A set dollar amount you pay for a specific service — like $25 for a primary care visit — usually after your deductible is met.
Coinsurance
Your share of costs after the deductible, expressed as a percentage. If your coinsurance is 20%, you pay 20% and your plan pays 80% of covered charges.
Out-of-Pocket Maximum
The yearly ceiling on what you pay for covered services. Once you reach it, your insurer covers 100% of covered costs for the rest of the plan year.
Health Savings Account (HSA)
A tax-advantaged account available with eligible high-deductible health plans that lets you save pre-tax money specifically for qualified medical expenses.
- Premium: Your monthly payment to keep the plan active, regardless of whether you use care.
- Deductible: What you pay first before insurance starts sharing costs. A $2,000 deductible means you cover the initial $2,000 in covered claims each year.
- Copay / Coinsurance: After the deductible, you typically still share costs. A copay is a flat fee (e.g., $30 per visit); coinsurance is a percentage (e.g., you pay 20%, insurance pays 80%).
- Out-of-Pocket Maximum: A yearly cap on your cost-sharing. Once you hit it, the plan covers 100% of covered services for the rest of the year.
A plan with a low premium often has a higher deductible, and vice versa. Neither extreme is automatically better — the right balance depends on how much care you typically use.
Use the SBC to Compare Plans Side by Side
Every health plan must provide a Summary of Benefits and Coverage (SBC) — a standardized two-page snapshot of what the plan covers and what you'll pay. Comparing the SBCs of two or three plans is the most efficient way to see real cost differences. Pay particular attention to the deductible, out-of-pocket maximum, and copay amounts for services you use regularly.
Plan Types: HMO, PPO, EPO, and HDHP
The plan type shapes both your costs and your flexibility in choosing providers.
- HMO (Health Maintenance Organization): You select a primary care physician who coordinates your care and provides referrals to specialists. Coverage is typically limited to in-network providers, keeping premiums lower.
- PPO (Preferred Provider Organization): No referrals required. You can see in-network or out-of-network doctors, though out-of-network visits cost more. Premiums are generally higher than HMOs.
- EPO (Exclusive Provider Organization): Like an HMO in that it covers only in-network care, but like a PPO in that referrals usually aren't required.
- HDHP (High-Deductible Health Plan): Features a higher deductible and lower premium. These plans are often paired with a Health Savings Account (HSA), which lets you set aside pre-tax dollars for qualified medical expenses.
HDHPs and HSAs Often Go Together
If you enroll in a qualifying High-Deductible Health Plan, you may be eligible to open a Health Savings Account (HSA). Contributions to an HSA are tax-deductible, grow tax-free, and can be withdrawn tax-free for qualified medical expenses. This combination can be cost-effective for people who are generally healthy but want a financial cushion for unexpected care.
How to Get Coverage
Most Americans obtain health insurance through one of four main pathways:
- Employer-sponsored coverage: The most common route. Your employer selects plan options and typically pays a portion of your premium. Enrollment usually occurs when you're hired or during an annual open enrollment window.
- ACA Marketplace: The Affordable Care Act created state and federal exchanges where individuals can compare and purchase plans. Income-based premium tax credits and cost-sharing reductions are available for those who qualify. Visit healthcare.gov or your state's marketplace to explore options.
- Medicaid: A joint federal and state program for people with low incomes. Eligibility rules vary significantly by state.
- Medicare: The federal program for adults 65 and older and certain younger individuals with qualifying disabilities.
Before committing to any plan, review the Summary of Benefits and Coverage (SBC) — a standardized document every plan must provide that outlines what's covered and what you'll pay. Our guide on questions to ask before enrolling can help you work through the SBC systematically.
Networks, Prior Authorization, and Other Things That Trip People Up
Even after you pick a plan, a few mechanics catch people off guard:
- Provider networks: Each insurer contracts with a specific set of doctors, hospitals, and labs. Receiving care outside that network can mean paying the full bill yourself, or significantly more than your normal cost-share. Always verify that a provider is in-network before scheduling non-emergency care.
- Prior authorization: Some services — certain surgeries, specialist visits, or brand-name drugs — require your insurer's approval before you receive them. Without it, the claim may be denied. Your doctor's office typically handles this, but it's worth confirming.
- Formularies: If you take prescription medications, check whether they appear on your plan's drug list (formulary) and at what cost tier. A medication that's free under one plan may cost hundreds under another.
- Balance billing: Even at an in-network facility, an anesthesiologist or radiologist may be out-of-network. Federal protections under the No Surprises Act limit balance billing in many of these situations, but understanding your rights beforehand matters.
Health insurance shares some structural similarities with other types of coverage — if you're curious how the concepts compare, see our overview of how auto insurance works in the US.
This article is for general informational purposes only and does not constitute personalized insurance, financial, legal, or medical advice. Coverage terms, costs, and eligibility vary by plan, provider, and state. Consult a licensed insurance professional for guidance specific to your situation.