Medicare Late Enrollment Penalty Calculator — Part B and Part D
Late Part B and late Part D almost always share one cause: the client simply didn't enrol. Enter their history once and see both penalties — and what they add up to together.
Nothing you enter leaves your browser — every calculation runs on your device
Client details
Used for both enrollment periods.
Active employment, 20+ employees. COBRA and retiree coverage do not count.
Exempts the Part D penalty entirely.
Projection assumptions
An assumption — adjust to your client.
The penalty is a percentage of a premium that rises each year.
Combined estimated penalty
Enter a date of birth and both coverage start dates to see the estimate.
Estimate only, based on CY2026 figures (standard Part B premium $202.90, Part D base $38.99). This is not an official determination. MedicareCopilot is not affiliated with or endorsed by CMS, Medicare, the Social Security Administration, or any government agency — official amounts and eligibility determinations are made by SSA and CMS. This tool provides general information only and is not medical, legal, or tax advice. Figures last verified 2026-07-27.
Part B
No penalty
Part D
No penalty
Catch this before it happens
MedicareCopilot tracks every client’s enrollment windows and warns you before a penalty can accrue — alongside CRM, quoting, enrollment, and commission tracking built for Medicare agents.
Common questions
Can you get both a Part B and a Part D late enrollment penalty?
Yes. They are separate penalties with separate rules, and someone who simply did not enrol in Medicare on time will often owe both.
The Part B penalty is 10% of the standard Part B premium per full 12-month period. The Part D penalty is 1% of the national base beneficiary premium per full uncovered month. Both last as long as you keep the coverage.
Which penalty is bigger?
The Part B penalty is almost always substantially larger, because it is a percentage of a much bigger premium and it compounds in 10% steps.
In 2026, one full year of Part B delay costs about $20.29 a month, while twelve uncovered Part D months cost about $4.68 a month.
Can either penalty be appealed?
The Part D penalty can be challenged through reconsideration, generally within 60 days of the notice, if creditable coverage was in place but not recorded.
The Part B penalty is far harder to reverse. Prevention — enrolling inside the Initial Enrollment Period or a valid Special Enrollment Period — is the only reliable protection.
Look at one part in detail
Part B Late Enrollment Penalty Calculator
Full Part B screening, including the employer-size and COBRA rules that decide whether a penalty applies at all.
Try it nowPart D Late Enrollment Penalty Calculator
Full Part D screening, the 63-day rule, and guidance on when the penalty can be appealed.
Try it nowEnrollment Period Finder
Every window they qualify for, so the next deadline never passes unnoticed.
Try it nowIRMAA Estimator
Income-based surcharges are added on top of both premiums, separately from any penalty.
Try it now