Both penalties are permanent, which is what makes missing a window different from missing a deadline elsewhere in insurance.
Part B. The penalty is 10 percent of the standard premium for every full 12 months you were eligible and not enrolled. Applied to the 2026 standard premium of $202.90 per month, two full years late works out to roughly $40 extra per month, and it stays on the premium for life. If you missed your initial window you generally enroll during the General Enrollment Period, January 1 to March 31.
Part D. The penalty is 1 percent of the national base beneficiary premium for each month you went without creditable drug coverage, recalculated annually and added to whatever plan you eventually choose.
When there is no penalty. If you delayed because you had employer coverage through active employment, you likely qualify for a Special Enrollment Period and no penalty at all. That window generally runs eight months for Part B after the employment or coverage ends, and about 63 days for Part D. This is the single most common reason people wrongly think they are in trouble.
If you think you missed something. Check before you assume. Social Security administers Part B enrollment and can confirm your record, and we can review your dates and options with you at no cost. Penalties can sometimes be corrected when an employer coverage record supports it.
Related on this site: Calculate a late enrollment penalty · Enrollment periods explained
Sources
- Part B late enrollment penalty (CMS) · accessed September 14, 2026
- Part D late enrollment penalty (CMS) · accessed September 14, 2026
- Apply for Medicare (Social Security) · accessed September 14, 2026
This page is general information, not advice about your specific situation, and it is not connected with or endorsed by the U.S. government or the federal Medicare program. Rules and figures change, so confirm current requirements with CMS, Social Security, or a licensed agent before you act. We do not offer every plan available in your area. Currently we represent 5 organizations which offer 300 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.