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If you sign up for Part B after your first window without qualifying job-based coverage in between, Medicare adds 10% to your monthly Part B premium for every full 12 months you could have had it but did not — and the surcharge usually lasts as long as you have Part B. Two years late means roughly 20% more, for life. If you missed your window, the General Enrollment Period (January–March) lets you sign up; a Special Enrollment Period, if one applies to you, avoids the penalty.
Apply this to my situationThe rules behind this
Signing up late for Part B usually costs extra for life
If you sign up for Part B after your first window ends and did not have coverage from current work in between, Medicare generally adds 10% to your Part B premium for every full 12 months you could have had Part B but did not — and the extra amount usually lasts as long as you have Part B.
Who this is for
People who delay Part B without qualifying job-based coverage.
What changes it
- Coverage from your own or a spouse’s current employer generally lets you delay without a penalty.
- COBRA and retiree coverage usually do not count as current-employment coverage.
The question that settles it
“Will I owe a Part B late-enrollment penalty, and how is it calculated for me?” — Social Security.
If you missed your window, there is a yearly catch-up period
The General Enrollment Period runs January 1 through March 31 every year. If you sign up then, coverage starts the month after you sign up. A late-enrollment penalty may still apply.
Who this is for
People who did not sign up during their first window and do not qualify for a Special Enrollment Period.
What changes it
- A Special Enrollment Period, if one applies, is usually the better route because it may avoid the penalty.
The question that settles it
“Do I qualify for a Special Enrollment Period, or do I need to wait for the General Enrollment Period?” — Social Security.
After job coverage ends you have 8 months for Part B
If you delayed Part B because you or your spouse had coverage from current work, you get a Special Enrollment Period: 8 months starting the month after the job or the coverage ends, whichever comes first. Signing up in that time avoids the Part B penalty.
Who this is for
People 65+ who kept coverage from their own or a spouse’s current employer.
What changes it
- COBRA and retiree coverage do not start or extend this period.
The question that settles it
“My job coverage ends on [date]. When does my 8-month Part B Special Enrollment Period end?” — Social Security.
Source: Social Security Administration — Sign up for Part B only ↗
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