When I started really digging into my own Medicare choices, I assumed “what’s covered” would be a simple yes-or-no list somewhere. It isn’t. Medicare covers things under specific conditions, and Medigap only pays on top of what Medicare already approved. The fastest way to get a wrong answer is to guess based on what a friend’s plan covered. So here’s what each piece actually covers and what neither one touches.
And — since this is really the question that matters — here’s exactly how to check for your own specific situation before you’re staring at a bill.
Quick answer: Original Medicare (Part A and B) covers hospital stays, doctor visits, outpatient care, preventive screenings, and durable medical equipment — but leaves you responsible for a 20% coinsurance with no annual cap. Medigap is private insurance that picks up some or all of that 20%, plus other gaps like the Part A deductible. Neither one covers routine dental, vision, hearing, or most prescription drugs.
To find out exactly what’s covered for a specific test, service, or item, use Medicare’s own coverage tool at medicare.gov/coverage, or call 1-800-MEDICARE directly. Don’t rely on a guess from a friend’s experience — coverage depends on the specific service, your diagnosis, and sometimes where you receive care.
What Original Medicare Actually Covers
Original Medicare is Part A and Part B together. If you want the fuller breakdown of how all four parts fit together, I laid that out in my Medicare basics guide.
Part A (hospital insurance) covers inpatient hospital stays, skilled nursing facility care for a limited time after a qualifying hospital stay, hospice care, and some home health care. Most people pay no premium for Part A since it’s funded by payroll taxes paid while working.
Part B (medical insurance) covers doctor visits, outpatient care, preventive services like annual wellness visits and screenings, durable medical equipment (wheelchairs, walkers, oxygen equipment), lab work, outpatient mental health services, and ambulance transportation. I broke down exactly what Part B costs, including the 2026 premium and IRMAA brackets, in my Part B cost guide.
Here’s the catch with Original Medicare alone: after you meet your Part B deductible, Medicare generally pays 80% of the approved amount. You’re responsible for the remaining 20% — and there’s no annual limit on how high that can add up.
What Medigap Adds on Top
Medigap (Medicare Supplement) insurance is private coverage that pairs with Original Medicare and picks up some or all of what Medicare doesn’t. Mainly, that means the uncapped 20% coinsurance and the Part A deductible — and depending on which lettered plan you choose, things like Part B excess charges and foreign travel emergency care. I went through how the plans differ, what Plan G versus Plan N actually means, and the enrollment timing that matters most in my Medigap guide.
If you are ready to see real Medigap quotes for your area, [AFFILIATE PLACEHOLDER: link to Medigap/Medicare plan comparison tool once approved] is where I would point you to compare plans side by side.
The important thing to understand about how Medigap works: it doesn’t cover anything Medicare itself doesn’t cover in the first place. Medigap pays its share only after Medicare has approved and paid its share of a claim. If Medicare denies something, Medigap has nothing to pay toward.
If you’re still weighing Medigap against Medicare Advantage as a different way to handle that same coverage gap, I put all three paths side by side in my Medicare coverage comparison guide.
What Neither One Covers
This catches people off guard most, so it’s worth saying plainly: Medigap only pays its share of a claim after Medicare has already approved and paid its share first. If Original Medicare doesn’t cover a service at all, Medigap has nothing to add on top of it. A Medigap policy doesn’t expand what’s covered — it only reduces your out-of-pocket cost on services Medicare already covers. Here’s what falls into that “neither one” category:
Routine dental care. Original Medicare and standardized Medigap plans don’t cover cleanings, fillings, dentures, or dental implants.
Routine vision care. Original Medicare doesn’t cover eye exams for glasses, or the glasses and contacts themselves. The one narrow exception: Medicare does cover corrective lenses after cataract surgery.
Hearing aids and hearing exams. Original Medicare and Medigap don’t cover hearing aids or routine hearing exams.
Prescription drugs. You’ll need a separate Part D plan for most medications — neither Original Medicare nor Medigap includes drug coverage.
Long-term custodial care. Neither one covers the kind of ongoing help with daily living that assisted living or nursing home stays often require. That’s a different planning conversation entirely — one I get into in more detail in my long-term care guide.
Cosmetic surgery and most elective procedures that aren’t medically necessary.
Medicare doesn’t cover most alternative and experimental treatments, including acupuncture, with one narrow exception it added for chronic low back pain.
Routine foot care, like the treatment of corns, calluses, or flat feet, outside of specific medical conditions like diabetes-related nerve damage.
Private-duty nursing and most care received outside the United States, though some Medigap plans do add limited foreign travel emergency coverage — one of the few things Medigap actually adds rather than just reduces the cost of.
The Real Process: How to Find Out What’s Covered for You
General coverage categories only get you so far. Here’s the actual process I’d use — and the one that gives you a real answer instead of a guess — for any specific test, service, or item.
1. Use Medicare’s own coverage tool. Go to medicare.gov/coverage and search by the name of the test, item, or service. It tells you whether Medicare covers it, and under what conditions (frequency limits, required diagnosis, etc.).
2. Call 1-800-MEDICARE. If the online tool doesn’t give you a clear answer, a phone call to Medicare directly (1-800-633-4227) can confirm coverage for your specific situation.
3. Check your MyMedicare.gov account. Once you’re enrolled, this shows your actual claims history, so you can see exactly what Medicare has already paid for.
4. Ask your doctor’s office to request a coverage determination before a procedure. For anything expensive or unusual, most billing offices can check ahead of time rather than leaving you to find out after the bill arrives.
5. For Medigap-specific questions, check your policy’s Outline of Coverage. Every Medigap insurer must provide this standardized document, which shows exactly what your specific plan letter covers. If you can’t find yours, call your insurer’s member services line directly.
6. Contact your State Health Insurance Assistance Program (SHIP). This is free, unbiased Medicare counseling available in every state, and it’s one of the most underused resources for exactly this kind of question.
7. If you’re on Medicare Advantage instead, this is a different process. Medicare Advantage plans set their own coverage rules within CMS requirements, so you’d check your plan’s Evidence of Coverage document and call the plan directly — not Medicare.gov or 1-800-MEDICARE.
Frequently Asked Questions
Does Medicare cover dental, vision, or hearing care?
No. Original Medicare and standardized Medigap plans don’t include routine dental, vision, or hearing coverage. Some Medicare Advantage plans bundle in limited versions of these benefits instead.
If Medicare denies a claim, will Medigap still pay?
No. Medigap only pays its share of a claim Medicare has already approved and paid on. If Medicare denies coverage for something, Medigap has nothing to contribute toward it.
Do I need to check coverage before every single doctor visit?
No — routine, well-established services like annual wellness visits are reliably covered. It’s worth checking specifically for anything unusual, new, or expensive, like a specialized test or piece of equipment.
Will my doctor’s office always know what’s covered?
Often, but not always. Billing offices deal with Medicare regularly and are usually right about common services, but for anything questionable it’s worth confirming directly with Medicare rather than relying solely on their word.
Is there a cost to check coverage through Medicare.gov or by phone?
No, both are free. There’s no reason to guess when confirming coverage costs nothing.
Does checking coverage work the same way for Medicare Advantage?
No. Medicare Advantage plans set their own rules within CMS guidelines, so you’d check your specific plan’s Evidence of Coverage and call the plan directly instead of Medicare itself.
Where to Go From Here
Understanding what’s covered is only half the picture — the other half is what it actually costs. My 2026 Part B cost guide covers the premium, deductible, and IRMAA brackets in detail, and my IRMAA calculator can estimate your specific premium in a few seconds. If you’re still deciding between Medigap and Medicare Advantage as your way of covering these gaps, my coverage comparison guide lays out both paths side by side.
As always — I’m not a financial advisor or licensed insurance agent, just someone working through these decisions myself and sharing what I learn. Coverage rules can be specific to your situation. For anything with real money on the line, it’s worth confirming directly with Medicare or a licensed Medicare counselor through your local State Health Insurance Assistance Program (SHIP), which offers free, unbiased help.