Part B Late Enrollment Penalty Calculator
Late Enrollment Penalty
What is the Part B penalty?
If you didn't sign up for Medicare Part B when you were first eligible — and you didn't have other qualifying coverage — you'll pay a penalty for as long as you have Medicare. The penalty is 10% of the standard premium for each full 12-month period you could have had Part B but didn't.
How long were you eligible for Part B but not enrolled?
Only count full months you could have had Part B but didn’t sign up. Don’t count time you had coverage through an employer or union.
How the Part B penalty works
If you don’t sign up for Medicare Part B during your Initial Enrollment Period and you don’t have qualifying coverage (like employer health insurance), Medicare adds a 10% surcharge to your monthly premium for each full 12-month period you could have had Part B but didn’t.
This penalty is not a one-time fee — it’s added to your monthly premium for as long as you have Part B. The penalty is based on the standard premium ($202.90 in 2026), which changes each year.
You won’t face a penalty if you had creditable coverage through an employer or union plan (for you or your spouse) during the gap. Time covered by employer insurance doesn’t count against you.
How the penalty is calculated
Medicare counts how many full 12-month periods you could have had Part B but didn't sign up. If you delayed 25 months, that's 2 full periods.
Your penalty is 10% of the standard Part B premium for each 12-month period. Two periods = 20% penalty. The 2026 standard premium is $202.9/month.
The penalty amount is added to your Part B premium every month. This continues for as long as you have Medicare — there's no end date.
Scenario: You delayed Part B for 30 months (2.5 years).
Full 12-month periods: 2 periods (30 ÷ 12 = 2.5, rounded down to 2)
Penalty rate: 10% × 2 = 20%
Monthly penalty: $202.9 × 20% = $40.58/month extra
Over 20 years, that's $9,739.2 in penalties.
When the penalty doesn't apply
You won't face a penalty if you had qualifying coverage during the delay:
- Employer or union coverage based on current employment (yours or a spouse's)
- TRICARE coverage
- VA health benefits (in some cases)
- Federal Employee Health Benefits (FEHB) with current employment
COBRA, retiree coverage, and marketplace plans do not count — you'd still face a penalty for delaying Part B while on these plans.
Not sure if you'll face a penalty?
The rules can be confusing, especially around employer coverage and Special Enrollment Periods. Our team can help you figure out your situation.
Get free help