Plain-English guide
Two Medicare penalties that last for life
Miss your Medicare sign-up window without other coverage and you can owe a penalty added to your premium — not once, but for as long as you have the coverage. The good news: both are easy to avoid once you know the rule.
The Part B penalty
For each full 12-month period you could have signed up for Part B but didn't, your premium rises10% — permanently. Two years late is roughly 20% more, every month, for the rest of your life. It's the clearest reason not to "wait and see" on Part B unless you have active employer coverage.
The Part D penalty
For drug coverage, the penalty is about 1% of the national base premium for every full month you went without Part D or other creditable drug coverage after your Initial Enrollment Period — added to your Part D premium for good. Go a couple of years uncovered and it adds up. The base amount is set yearly; confirm it at Medicare.gov.
How to avoid both
- · Sign up during your Initial Enrollment Period (the 7 months around your 65th birthday) unless you have active coverage from a current job.
- · If you have creditable coverage through work, enroll during the Special Enrollment Period when it ends — and keep the proof.
- · Don't let a Part D gap sneak up on you: even a cheap drug plan avoids the penalty clock.
Free help first
Not sure which window is yours? Your State Health Insurance Assistance Program (SHIP) gives free, unbiased Medicare counseling: find your local SHIPor call 1-877-839-2675. Or check Medicare.gov.
Common questions
How much is the Part B late-enrollment penalty?
Your Part B premium goes up 10% for each full 12-month period you could have had Part B but didn't sign up — and you pay that higher premium for as long as you have Part B. It's not a one-time fee; it's permanent, so signing up on time matters. Source: Medicare.gov.
How is the Part D drug penalty calculated?
It's 1% of the 'national base beneficiary premium' for each full month you went without Part D or other creditable drug coverage after your Initial Enrollment Period. That amount is added to your Part D premium for as long as you have Part D, and the base figure is set each year. Confirm the current figure at Medicare.gov. Source: Medicare.gov.
Can I avoid the penalty if I have coverage through work?
Yes. If you have 'creditable' coverage — for Part B, active employer coverage through your or a spouse's current job; for Part D, drug coverage at least as good as Medicare's — you generally won't owe a penalty, as long as you enroll during the Special Enrollment Period when that coverage ends. Keep proof of creditable coverage. Source: Medicare.gov.
Source: Medicare.gov (Part B and Part D late-enrollment penalties, creditable coverage, enrollment periods). Penalty percentages are set by federal rule; the Part D base premium is set each year — confirm current figures at Medicare.gov. We are not connected with or endorsed by the U.S. government. General information, not insurance advice. Last reviewed: 2026.