Part B Penalty Calculator: Your 2026 and 2027 Monthly Cost
The penalty is 10% of the standard Part B premium for each full 12-month period you could have had Part B but didn't, rounded to the nearest 10 cents. Months are counted from the end of your Initial Enrollment Period, or of an 8-month special period, to when Part B starts. (Medicare.gov: avoid late penalties)
| Time without Part B | Penalty | Extra per month in 2026 |
|---|---|---|
| Under 12 months | 0% | $0 |
| 12–23 months | 10% | $20.30 |
| 24–35 months | 20% | $40.60 |
| 36–47 months | 30% | $60.90 |
| 60–71 months | 50% | $101.50 |
The penalty rises each year with the premium: $202.90 in 2026 and $209.50 Projected projected for 2027 (CMS 2026 premiums). Switch years in the calculator.
Medicare Part B Late Enrollment Penalty: When It Does Not Apply
There's no penalty if you had group health coverage from your own or your spouse's current job and sign up within 8 months after that job or coverage ends. That's the special enrollment period, and it covers most people who kept working past 65.
What does not protect you:
- COBRA, even if it's from your old employer
- Retiree health plans
- VA coverage or individual Marketplace plans
There are narrower exits too: "exceptional conditions" special periods (for example, a disaster or an employer's mistake), and enrolling in a Medicare Savings Program, which removes the Part B penalty.
Our take: every year of waiting adds another 10%
If you're past your window with no job-based coverage, don't wait for a better moment — sign up in the next General Enrollment Period (January 1 to March 31). Not 65 yet? Find your Medicare sign-up window now, and see your full premium with IRMAA on the Medicare premium calculator. On COBRA? Read COBRA and Medicare: why COBRA does not protect you.