What does health insurance actually cover? A straightforward guide

The core: what nearly every plan covers

Marketplace plans are required to cover a standard set of categories called Essential Health Benefits, and most employer plans follow the same outline even when they technically don't have to:

• Doctor visits
• Emergency services
• Hospital stays
• Preventive care
• Prescription drugs
• Mental health and substance use services
• Maternity and newborn care
• Rehabilitation services
• Pediatric services

The rest of this guide walks through the big ones — and then the exclusions, which is where the surprise bills usually come from.

Preventive care: free when you stay in network

Most preventive services cost you nothing when you use an in-network provider. That includes annual physicals; blood pressure, diabetes and cholesterol tests; cancer screenings like mammograms and colonoscopies; vaccinations, from flu shots to COVID-19; and birth control and counseling.

Why so generous? Because catching a problem early costs your insurer far less than treating it late. Keeping you healthy is the one place your interests and theirs line up perfectly — so use it.

Doctor and specialist visits

Your plan pays a large share of visits to your primary care doctor and to specialists like dermatologists or cardiologists. Your share is either a copay (a flat fee, say $25) or coinsurance (a percentage of the visit, say 20%).

The catch is the network. See a doctor who's out-of-network and your share can jump dramatically. Check before you book, not after.

Emergency and hospital care

Every plan covers ER visits and hospital stays, including surgery and overnight care — and it must cover emergency services even if the hospital is out-of-network. That's the good news.

The honest news: this is where cost-sharing bites hardest. An ER copay of $250 or more is common, and a hospital stay often runs 20% coinsurance or higher until you hit your out-of-pocket maximum. Covered doesn't mean cheap.

Prescription drugs

Every plan keeps a formulary — a list of covered medications sorted into tiers, from cheapest to priciest: generic drugs, preferred brand-name drugs, non-preferred brand-name drugs, and specialty drugs. Your copay or coinsurance depends on the tier.

If your medication isn't on the formulary at all, you could pay full price — or you can request an exception. Better yet: check the formulary before you enroll, not at the pharmacy counter.

Mental health and substance use treatment

Federal parity law — the Mental Health Parity and Addiction Equity Act — requires insurers to cover mental health and addiction care on the same terms as medical and surgical care. That means therapy and counseling, psychiatric evaluations, inpatient mental health treatment, and substance use programs are all covered benefits, not extras. As always, in-network providers keep your share down.

Maternity and newborn care

Every ACA-compliant plan must cover pregnancy, childbirth and newborn care — even if you're already pregnant when you enroll. That includes prenatal visits, labor and delivery, postnatal checkups, and newborn screenings. Many plans also cover lactation support and breastfeeding equipment like breast pumps.

Pediatric services

If your plan covers dependents, it must include pediatric care: routine well-child visits, immunizations, and — for kids under 19 — vision and dental. Through in-network providers, these are often fully covered.

The four numbers that decide what you pay

"Covered" doesn't mean free. Four numbers turn a covered service into your actual bill:

• Deductible — what you pay before the plan starts paying.
• Copay — a fixed amount for a specific service, like $25 per visit.
• Coinsurance— your percentage of costs after you've met the deductible.
• Out-of-pocket maximum— the most you'll pay in a year; after that, the plan pays 100%.

Here's how they stack: with a $2,000 deductible, you pay the first $2,000 of bills yourself. After that you might owe 20% coinsurance until your spending hits the out-of-pocket max — say $8,000 — and from there the plan covers everything. Two plans can be "covered" for the exact same care and cost you thousands of dollars apart.

The habit that saves the most: stay in network

Insurers negotiate discounted rates with specific doctors, hospitals and clinics — your in-network providers. Use them and you get the negotiated price. Go out-of-network and care is either not covered at all or reimbursed at a much lower rate, with you picking up the difference.

So the whole game, in one paragraph: know your plan's core benefits, know its exclusions, know your four cost numbers, and stay in network. Do that and health insurance stops being a maze — it's just a contract, and now you can read it.