What Is Medicare Part B? Coverage, Costs and Enrollment

Medicare Part B is the medical insurance portion of Medicare. While Part A covers hospital stays, Part B covers the things you're more likely to use regularly: doctor visits, outpatient procedures, lab tests, preventive screenings, medical equipment, and some home health care. Almost everyone on Medicare has Part B.

What Part B Costs in 2026

The standard Part B premium for 2026 is $202.90 per month. Most people pay this amount, which is typically deducted from their Social Security check. Higher-income beneficiaries pay more through Income-Related Monthly Adjustment Amounts (IRMAA). The annual deductible is $283. After you meet it, Part B generally pays 80% and you pay 20% coinsurance.

What Part B Covers

Doctor and specialist visits. Outpatient surgery. Diagnostic tests and lab work. Mental health services (outpatient). Durable medical equipment (wheelchairs, walkers, oxygen). Ambulance services when medically necessary. Preventive services including flu shots, mammograms, colonoscopies, diabetes screenings, and an annual wellness visit, all at no cost to you.

What Part B Doesn't Cover

Routine dental, vision exams for glasses, hearing aids, most prescription drugs (that's Part D), long-term care, and cosmetic procedures. If you need these, you'll have to get coverage through Medicare Advantage, a standalone plan, or pay out of pocket.

When to Sign Up

Your Initial Enrollment Period for Part B starts 3 months before the month you turn 65 and ends 3 months after. If you're still working and have employer coverage when you turn 65, you can delay Part B without penalty and sign up during a Special Enrollment Period when that coverage ends. If you miss your window and don't qualify for an exception, the late enrollment penalty adds 10% to your Part B premium for each full 12-month period you could have had Part B but didn't. That penalty lasts as long as you have Part B.