Medicare Part B: Eligibility, Coverage, and Cost
Medicare Part B is the medical insurance portion of Original Medicare. It covers doctor visits, outpatient care, preventive services, lab work, and durable medical equipment.
While Part B pays for a large share of your medical expenses, you're still responsible for deductibles and 20% coinsurance — with no annual out-of-pocket maximum.
That's one of the main reasons I often recommend a Medigap plan for people who can comfortably afford the premium.
Here's everything you need to know, from what's covered to what it costs in 2026.
Medicare Part B at a Glance
- Covers outpatient medical care: doctor visits, labs, diagnostics, durable equipment
- Standard monthly premium: $202.90 (2026), higher if IRMAA applies
- Annual deductible: $283
- You pay 20% coinsurance after the deductible — with no annual out-of-pocket limit, so costs can keep adding up all year
- Most preventive services (screenings, vaccines, annual wellness visit) are covered at no cost
What Is Medicare Part B?
If Part A is your safety net for hospital stays, Part B is your everyday coverage — the doctor's office, lab tests, outpatient services, and preventive screenings.
You pay a monthly premium, meet a deductible, then share costs with Medicare through coinsurance, similar to a traditional health plan.
One term you'll see throughout this article: Medicare-approved amount. That's the amount Medicare agrees to pay a provider for a service — often lower than the provider's usual charge.
Your coinsurance is a percentage of that approved amount, not the full billed price, as long as the provider "accepts assignment."
| Part A | Part B |
|---|---|
| Hospital insurance | Medical insurance |
| Inpatient care | Outpatient care |
| Skilled nursing facility care | Doctor visits & specialists |
| Hospice care | Preventive care & screenings |
| Per-benefit-period deductible | Annual deductible |
Eligibility & Enrollment
Most people qualify for Part B at age 65.
Younger individuals receiving Social Security Disability Insurance (SSDI), or diagnosed with ALS or End-Stage Renal Disease (ESRD), may qualify earlier.
If you're already collecting Social Security or Railroad Retirement benefits, you're enrolled automatically.
Medicare mails your card about three months before your 65th birthday, and coverage simply starts on time.
No action is needed unless you want to delay it — for example, because you're still covered under a spouse's or employer's group plan.
If you're not yet collecting those benefits, you'll need to sign up yourself during your Initial Enrollment Period (IEP).
It's a 7-month window: 3 months before your birthday month, your birthday month, and 3 months after.
For example, a June birthday means an IEP running March 1 through September 30.
Enrolling in the first 3 months typically avoids any gap before coverage starts.
Miss it, and you're limited to the General Enrollment Period (Jan 1–Mar 31), with coverage starting in July — plus a permanent late-enrollment penalty.
If you have qualifying employer coverage, a Special Enrollment Period lets you sign up later without penalty, typically up to 8 months after that coverage ends.
See our full Medicare Enrollment Periods guide for every window and deadline.
Under 65? You may qualify early with 24 months of SSDI, or immediately with ALS or End-Stage Renal Disease.
For the full breakdown of disability-based eligibility, see our Medicare eligibility guide.
Find Your Enrollment Window
Answer a few questions below to see your personal enrollment deadlines and next steps.
Medicare Enrollment Wizard
Answer a few questions to find your enrollment window and next steps.
This matters because only large-employer coverage lets you delay Part B without a penalty.
This tool gives a general estimate based on common Medicare enrollment rules. Your exact dates and eligibility should always be confirmed with Social Security or Medicare.gov.
Who Should Get Part B?
Nearly everyone enrolling in Medicare should have Part B — it covers the care you'll actually use most: doctor visits, labs, and preventive screenings.
The main exception is if you're still working with active employer coverage. In that case, you may be able to delay Part B penalty-free until that coverage ends.
What Does Medicare Part B Cover?
Part B covers medically necessary outpatient services plus a strong slate of preventive care.
Most preventive care costs you nothing if your provider accepts Medicare assignment.
Doctor & Outpatient Care
- Primary care visits
- Specialist visits
- Outpatient surgery
- Physical & mental health therapy
- Ambulance transport
Diagnostic Services
- X-rays, MRIs, CT scans
- Lab work & bloodwork
- Diagnostic imaging
Medical Equipment
- Walkers & wheelchairs
- Oxygen equipment
- CPAP machines
- Clinic-administered injections/infusions
Preventive Care
- Annual wellness visit
- Flu & COVID-19 vaccines
- Cancer screenings (mammograms, colonoscopies)
- Diabetes & cardiovascular screenings
Common Services Part B Doesn't Cover
- Routine dental care
- Routine vision care
- Hearing aids
- Long-term custodial care
- Most prescription drugs (see our Medicare Health Plan Types guide)
- Most medical care outside the U.S.
If these gaps matter to you, some Medicare Advantage plans bundle in dental, vision, and hearing benefits.
Standalone dental and vision plans are also available separately from Original Medicare and Medigap.
How Much Does Part B Cost in 2026?
Curious what a late enrollment penalty would actually cost you? Use the calculator below.
Medicare Part B Penalty Calculator
Estimate the late enrollment penalty you could face for Part B.
Used to estimate when your Initial Enrollment Period (IEP) ended.
This is an estimate for planning purposes only, based on the 2026 Medicare Part B premium. Only Social Security can confirm your official enrollment date and penalty amount.
- Monthly premium: $202.90 standard, more if you're above the IRMAA income threshold
- Annual deductible: $283 — resets every calendar year, regardless of when you enrolled
- Coinsurance: 20% of the Medicare-approved cost for most services, after your deductible
- Out-of-pocket limit: none — every service all year is subject to that 20%, with nothing to cap the total, which is the single biggest reason people add a Medigap plan
Here's how the pieces work together: say you see a specialist in March for a Medicare-approved $500 visit — your first service of the year.
You'd pay the $283 deductible first, then 20% of the remaining $217 (about $43) — roughly $326 total.
Every visit after that in the same year is just the 20% coinsurance, since your deductible is already met.
Now picture a harder year: a hip replacement, follow-up visits, and months of physical therapy, totaling $60,000 in Medicare-approved charges.
Part B still only covers 80%. Your 20% share is $12,000 — and Medicare won't stop sharing costs once you hit some threshold, because there isn't one.
That's the scenario Medigap is built for: it's not the routine visits that create risk, it's the year you can't predict.
If your income is above a certain threshold, you'll pay an Income-Related Monthly Adjustment Amount (IRMAA) on top of the standard premium.
The Social Security Administration determines this automatically, using the Modified Adjusted Gross Income (MAGI) from your tax return filed two years earlier.
You don't need to apply or calculate it yourself — SSA will notify you by mail if it applies.
2026 IRMAA Brackets — Single Filers
| 2025 Income (MAGI) | IRMAA | Total Monthly Premium |
|---|---|---|
| $109,000 or less | $0.00 | $202.90 |
| $109,001 – $137,000 | $81.20 | $284.10 |
| $137,001 – $171,000 | $202.90 | $405.80 |
| $171,001 – $205,000 | $324.60 | $527.50 |
| $205,001 – $499,999 | $446.30 | $649.20 |
| $500,000 or more | $487.00 | $689.90 |
2026 IRMAA Brackets — Married Filing Jointly
| 2025 Joint Income (MAGI) | IRMAA | Total Monthly Premium |
|---|---|---|
| $218,000 or less | $0.00 | $202.90 |
| $218,001 – $274,000 | $81.20 | $284.10 |
| $274,001 – $342,000 | $202.90 | $405.80 |
| $342,001 – $410,000 | $324.60 | $527.50 |
| $410,001 – $749,999 | $446.30 | $649.20 |
| $750,000 or more | $487.00 | $689.90 |
My take: After helping Medicare beneficiaries for more than 15 years, this is the Part B feature people underestimate most.
Many assume Medicare works like employer insurance with an annual maximum. It doesn't.
That's why even a single outpatient surgery can leave you with a four-figure bill — no ceiling, no matter how many times it happens in a year.
Medicare itself is excellent coverage. This one gap is the exception, and it's the part I make sure every client understands before they decide how to structure their plan.
Cancer treatment, a joint replacement, ongoing dialysis — these aren't rare, and the 20% coinsurance follows you through all of it, with no year-end stopping point.
Can You Drop Part B?
Yes, but carefully. People typically drop it if they have active employer coverage or VA benefits. Before you do:
- Lifetime penalty: 10% added to your premium for every 12 months you go without Part B or other creditable coverage
- Coverage gap: re-enrolling means waiting for the General Enrollment Period, with a start date months away
- Medigap/Advantage impact: most plans require continuous Part A and Part B enrollment
Dropping isn't as simple as canceling a subscription.
You'll need to request Form CMS-1763 from Social Security and complete a short interview with a representative.
Your coverage ends on the first day of a future month you choose — keep it active until that date is confirmed to avoid a lapse.
Talk to a Medicare specialist first if you're not certain your other coverage is creditable.
Why I Recommend Pairing Part B with Medigap
Because Part B only covers 80% of costs with no spending cap, most of my clients pair it with a Medigap (Medicare Supplement) plan.
That 20% has no ceiling on its own — Medigap is what puts one back in place.
Medigap fills that 20% gap and lets you see any provider who accepts Medicare — no networks, no referrals.
Plans like Plan G often cover nearly everything past your deductible.
Take that $5,000 outpatient surgery: without Medigap, you owe $1,000.
With Plan G, once you've met the $283 Part B deductible, that $1,000 is covered in full.
Medigap is different from a Medicare Advantage plan.
Medigap works alongside Original Medicare to cover your cost-sharing. Medicare Advantage replaces Original Medicare with a private plan that has its own network.
You can't have both at the same time. See our full Medigap vs. Medicare Advantage comparison for more.
Want the full breakdown of plan letters and what each one covers? Read our guides to Medigap plans, Plan G, and Plan N.
Final Thoughts
Part B is essential — it's the coverage behind your wellness visits, screenings, and outpatient care.
But its 20% coinsurance and lack of a spending cap mean it rarely works well alone.
Pairing it with the right Medigap plan is, in my experience, the difference between Medicare that's predictable and Medicare that's a financial gamble.
If you're approaching 65, already enrolled, or helping a loved one figure this out — we can help.
Our licensed advisors can walk you through your options, free, with no obligation.
Additional Resources
- Medicare.gov — official coverage lookup, plan comparisons, and enrollment tools
- Social Security Administration: Medicare — enroll, manage your benefits, or request an IRMAA reconsideration
- Medicare.gov: Costs — official current-year premium, deductible, and coinsurance figures
- 1-800-MEDICARE (1-800-633-4227) — 24/7 phone support directly from Medicare
FAQs
- Is Medicare Part B mandatory?
- Can I delay Part B if I'm still working?
- Does Medicare Part B cover telehealth?
- Does Part B cover emergency room visits?
- Does Part B cover prescription drugs?
- What is the Part B deductible?
- Is Part B free?
