Medicare Part B late enrollment penalty — how it works and how to avoid it
If you don't enroll in Medicare Part B when first eligible — and you don't have other creditable coverage — Medicare adds a permanent 10%-per-year penalty to your monthly premium. Here's how the penalty is calculated, who it applies to, and the exact rules for avoiding it.
Key takeaways
- The Part B late enrollment penalty is 10% of the standard premium for every full 12 months you went without Part B when you should have had it.
- The penalty is permanent — it sticks for as long as you have Part B. It doesn't disappear after a certain number of years.
- Active employer coverage from current work generally counts as creditable coverage and protects you from the penalty.
- If you're 65+ and on COBRA or retiree-only coverage, that does not count as creditable coverage — you must enroll in Part B.
How the Part B late enrollment penalty is calculated
The penalty is straightforward: your Part B premium goes up 10% for each full 12-month period you could have had Part B but didn't. Two missed years = +20%. Five missed years = +50%. And it's permanent — it doesn't expire.
In 2026, the standard Part B premium is approximately $185/month. So a beneficiary with a 50% lifetime penalty pays roughly $278/month for the rest of their life on Medicare. Over 20 years of retirement, that's about $22,000 in extra premium.
The penalty is added to your monthly Part B premium and deducted from your Social Security check (if you receive Social Security) — or billed quarterly if not.
Who gets the penalty (and who doesn't)
The penalty applies if you didn't enroll in Part B during your Initial Enrollment Period (IEP) — the 7-month window around your 65th birthday — and you don't qualify for a Special Enrollment Period (SEP).
You usually do NOT get the penalty if:
- You had active employer coverage from current work (yours or your spouse's) for at least one year of employment with that employer covering 20+ employees. This triggers a SEP that lets you delay Part B without penalty.
- You qualify for a Special Enrollment Period for another reason — moving back from outside the U.S., for example.
- You never qualified for premium-free Part A (rare — typically only people without enough work history).
You DO get the penalty if you delayed Part B because of:
- COBRA coverage. COBRA does NOT count as creditable coverage at age 65+. We see this mistake constantly.
- Retiree-only health coverage. This also doesn't count — once you stop working, the SEP clock starts.
- VA health benefits. VA coverage is creditable for Part D drug coverage but NOT for Part B medical coverage.
- An ACA Marketplace plan. Marketplace coverage is also not creditable for Medicare purposes.
Real-world examples
Linda, age 68: Turned 65, was on COBRA from her old job. Thought COBRA counted as coverage. Enrolled in Part B 3 years late. Her penalty: 30% × $185 = $55.50/month extra, forever. Over 20 retirement years: ~$13,300.
James, age 67: Worked full-time at a 200-person company until 67. His employer health plan was creditable. When he retired, he had an 8-month SEP to enroll in Part B. He enrolled in month 3. No penalty.
Diane, age 70: Took early Social Security at 62 but said no to Medicare Part B at 65 because she was healthy and didn't want the premium. Five years later she needed surgery. Penalty: 50% × $185 = $92.50/month extra, forever.
How to avoid the penalty
The simplest rule: if you're turning 65 and you don't have active coverage from current employment, enroll in Part B during your IEP. Period.
If you DO have active employer coverage, get a letter of creditable coverage from your employer's HR or insurance carrier before your IEP ends. Keep it. You may need to show it to Social Security to prove the SEP applies.
When you eventually leave that employer coverage, you have an 8-month SEP to enroll in Part B without penalty. Don't wait — enroll within the first month or two so you don't have a coverage gap.
Can you appeal the penalty?
Yes, but the bar is high. You can request a reconsideration with Social Security if you can show that you got incorrect information from a federal employee or your employer that caused you to delay Part B. Bad advice from a friend, a magazine article, or a non-Medicare insurance broker generally does not qualify.
Medicare also recently introduced a 'good cause' exception for some Special Enrollment Period missed deadlines. The rules are case-by-case and a SHIP counselor (free state Medicare counseling) is the best place to start.
Questions about your specific situation?
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