How the penalty works
If you do not sign up for Part B when you are first eligible and you do not qualify for a Special Enrollment Period, your premium increases by 10% of the standard premium for each full 12-month period you could have had Part B but did not. Only complete 12-month periods count, so 23 months of delay counts as one period. The penalty is recalculated against each year's standard premium and lasts as long as you have Part B.
2026 examples
| Full years delayed | Penalty | Your Part B premium (2026) | Extra per year |
|---|---|---|---|
| 0 | None | $202.90 | $0 |
| 1 | 10% ($20.29) | $223.19 | $243.48 |
| 2 | 20% ($40.58) | $243.48 | $486.96 |
| 3 | 30% ($60.87) | $263.77 | $730.44 |
| 5 | 50% ($101.45) | $304.35 | $1,217.40 |
Income-related surcharges (IRMAA) are charged on top of the standard premium and are separate from the penalty.
How to avoid it
- Sign up during your Initial Enrollment Period (the 7 months around your 65th birthday). See the dates.
- Use a Special Enrollment Period if you or your spouse are still working with employer coverage: you have 8 months after the job or coverage ends. See how it works.
- Remember what does not count: COBRA, retiree coverage, and Marketplace plans do not protect you from the penalty.
If you are already late
You can sign up during the General Enrollment Period, January 1 to March 31 each year. Coverage starts the month after you sign up. The penalty still applies.
Part A has a penalty too
Most people get premium-free Part A. If you must pay a Part A premium and you delay signing up, your premium rises by 10% for twice the number of years you could have enrolled but did not.