Program Basics
Medicare Part B
Quick answer
Medicare Part B is the medical insurance half of Original Medicare. It covers doctor visits, outpatient care, preventive screenings, mental health services, and durable medical equipment.
Plain-English definition
Part B pays 80% of the Medicare-approved amount after you meet the annual deductible. Most people pay the standard monthly Part B premium set by CMS each year; higher earners pay more via IRMAA.
Why it matters
You generally need Part B to enroll in a Medicare Advantage or Medigap plan and to avoid a permanent late-enrollment penalty.
A simple example
You visit your primary-care doctor. Medicare pays 80% of the approved amount; you owe 20% coinsurance.
Common mistakes & misconceptions
- Delaying Part B without qualifying employer coverage — the penalty is permanent.
- Assuming Part B covers prescription drugs — it doesn't.
Child topics
Related terms
Medicare Part A
Medicare Part A is hospital insurance. It covers inpatient hospital stays, skilled nursing facility care after a qualifying stay, home health care, and hospice. Most people get Part A premium-free at 65.
IRMAA (Income-Related Monthly Adjustment Amount)
IRMAA is an income-based surcharge added to Medicare Part B and Part D premiums for higher earners. Social Security calculates it from your IRS tax return two years prior.
Medicare Advantage (Part C)
Medicare Advantage, also called Part C, is a way to receive your Medicare benefits through a private insurance plan approved by Medicare. Plans bundle Part A and Part B, usually include Part D drug coverage, and often add dental, vision, and hearing.
Medicare Part D
Medicare Part D is prescription drug coverage sold by private insurance companies approved by Medicare. You get it either as a stand-alone drug plan (PDP) with Original Medicare or bundled inside most Medicare Advantage plans.
Frequently asked questions
How much is the Part B premium?+
CMS sets it each year. Higher-income beneficiaries pay more via IRMAA.
People also ask
When should I enroll in Part B?
During your Initial Enrollment Period unless you have qualifying employer coverage.
Sources & references
📚 Where this information comes from
- Medicare.gov — official U.S. government site for people with Medicare ↗Primary source for benefits, enrollment periods, and plan comparison.
- CMS.gov — Centers for Medicare & Medicaid Services ↗Federal rulemaking, program updates, and official guidance.
- Social Security Administration — Medicare enrollment & premiums ↗Enrollment, premium withholding, and IRMAA determinations.
When you're ready, compare plans on your own terms
See Medicare Advantage plans from the insurance companies we represent, or walk the course with a licensed agent whenever you'd like a second set of eyes.
We help compare Medicare Advantage plans from the insurance companies we represent, and we don't offer every plan available in your area.
Medicare Caddies is an independent insurance agency. We are not affiliated with, endorsed by, or connected to the U.S. government, the federal Medicare program, or the Centers for Medicare & Medicaid Services (CMS). We help compare Medicare Advantage plans from the insurance companies we represent, and we don't offer every plan available in your area.