Medicare Part B: Doctors, Outpatient Care, and the Bill People Miss

If Part A is the hospital bed, Part B is just about everything else medical. Your doctor visits. Lab work. Outpatient surgery. Physical therapy. Durable medical equipment like a walker or a CPAP. Most preventive care. Even some drugs, the kind given in a doctor's office rather than picked up at a pharmacy. Part B is the part you'll actually use the most. It's also where the bill people don't see coming lives.

What Part B covers

Two big categories. Medically necessary services — the doctor visits, surgeries, tests, and equipment you need to diagnose or treat a condition. And preventive services — screenings, shots, the annual wellness visit, a lot of which costs you nothing out of pocket. If a procedure happens and you go home the same day, odds are it ran through Part B, not Part A.

What Part B costs in 2026

There are two predictable numbers, and then the one that isn't.

Most people pay the $202.90 premium right out of their Social Security check. You meet the $283 deductible once for the year, and then Part B covers 80% of the Medicare-approved amount for your care. You're on the hook for the other 20%.

The bill people miss: that 20% never stops

Here's the part that surprises folks. The 20% coinsurance has no ceiling. None. On a routine doctor visit, 20% is pocket change. But Part B also covers the big stuff — chemotherapy, dialysis, a major outpatient surgery. And it pays 80% on all of it, which means you owe 20% on all of it, with nothing to stop the meter.

Run the math. Say you need an outpatient procedure and the Medicare-approved amount comes to $40,000. Part B pays 80%. Your 20% is $8,000 — and there's no annual maximum that caps it. Have a rough year with ongoing treatment, and that 20% keeps adding up. People hear "Medicare pays 80%" and feel covered. The 80% is real. The missing 20% is the part nobody mentions until the statement shows up.

That gap is exactly why most people don't stop at Original Medicare. A Medicare Supplement like Plan G picks up that 20% so your exposure on the Part B side becomes predictable. The other path is the Medicare Advantage route, which builds in a yearly out-of-pocket maximum but runs on a network. Two ways to close the same gap, and which one fits comes down to your doctors and your math — that's the conversation worth having.

If you earn more, you pay more: IRMAA

The $202.90 premium is the standard. Higher earners pay an add-on called IRMAA — the income-related monthly adjustment amount. In 2026 it starts once your income passes $109,000 as a single filer or $218,000 filing jointly, and it climbs from there. At the top brackets, the Part B premium can run up past $689 a month per person.

The wrinkle that catches people: IRMAA looks back two years. Your 2026 surcharge is based on your 2024 tax return. So a one-time bump — selling a house, a big Roth conversion, a year with extra income — can raise your Medicare premium two years later. If that's you, it's worth planning around. Run your numbers on the IRMAA calculator.

Don't skip Part B without a good reason

Part B is optional on paper, but skipping it without creditable coverage — like an active employer plan you're still working under — triggers a late enrollment penalty that's permanent. It adds 10% to your premium for every full 12 months you could've had Part B and didn't, and it stays on the bill for as long as you have Part B. If you're turning 65 and not sure whether your current coverage counts, check before you delay. The Original Medicare page walks through enrollment timing.

Frequently asked questions