About the Medicare Late Enrollment Penalty Calculator
Medicare charges a permanent surcharge if you sign up late without qualifying coverage. This calculator converts the time you went without coverage into the 2026 dollar amount added to your premiums: 10% of the standard Part B premium for each full 12-month period you could have had Part B, 1% of the national base beneficiary premium for each month without creditable drug coverage under Part D, and the 10% Part A surcharge for people who must buy Part A.
It is for new enrollees who missed their Initial Enrollment Period, people who dropped employer or retiree drug coverage, and anyone checking a penalty shown on a Medicare notice. The 2026 figures are the $202.90 standard Part B premium, the $38.99 Part D national base beneficiary premium and Part A premiums of $565 (fewer than 30 quarters of work) or $311 (30–39 quarters).
Do not count months when you had coverage from current employment (yours or a spouse’s) that let you use a Special Enrollment Period, or months with creditable drug coverage. Part B and Part D penalties are recalculated each year from that year’s base amounts and generally last for as long as you have the coverage; the Part A penalty lasts twice the number of full years you were late. Penalties are rounded to the nearest 10 cents, as on Medicare.gov.
With the default inputs, the total monthly penalty (2026) is $46.08. Change any value above to recalculate instantly.
How to use the medicare late enrollment penalty calculator
- 1Count the months you were eligible for Part B but not enrolled and had no employer coverage from active work.
- 2Count full months after your Initial Enrollment Period without Part D or creditable drug coverage.
- 3If you must buy Part A, enter how many months late you were and which premium applies.
- 4Read the monthly penalty for each part and the combined total.
- 5Use the 10-year figure to weigh the cost of delaying enrollment further.
Formula and method
Part B: count the full 12-month periods during which you could have had Part B but did not (excluding time covered by current-employment group coverage). Each full period adds 10% of the standard premium — $202.90 in 2026. Two years late means 20%, or $40.58 a month on top of the premium.
Part D: multiply the number of full months you went without Part D or other creditable drug coverage by 1% of the national base beneficiary premium ($38.99 in 2026) and round to the nearest 10 cents. Part A (only for people who must buy it): a flat 10% of the premium, payable for twice the number of full years you were late. The 10-year projection holds 2026 amounts constant; in practice Part B and D penalties rise as the base premiums rise.
- ⌊months ÷ 12⌋
- Full 12-month periods without Part B
- $38.99
- 2026 Part D national base beneficiary premium
- $202.90
- 2026 standard Part B premium
Worked examples
Two years late for Part B, 14 months without drug coverage
Twenty-four months is two full years, so the Part B penalty is 20% of $202.90 = $40.58, making the premium about $243.50. Fourteen months without drug coverage is 14% of $38.99 = $5.46, rounded to $5.50. Together the penalties add $46.08 a month.
Dropped drug coverage for 30 months
30 × 1% × $38.99 = $11.697, which rounds to $11.70 a month added to any Part D premium. At 2026 amounts that is $1,404 over ten years.
Late for Part B and premium Part A
Forty months contains three full years, so Part B rises 30% ($60.87). Being 30 months (two full years) late for $565 Part A adds 10% = $56.50 for four years. Over ten years at 2026 amounts the penalties total about $10,016.
Frequently asked questions
How is the Medicare Part B late enrollment penalty calculated?+
Your monthly Part B premium goes up 10% for each full 12-month period you could have had Part B but did not sign up. In 2026 each 10% equals $20.29 on the $202.90 standard premium, and the penalty usually lasts as long as you have Part B.
How is the Part D late enrollment penalty calculated?+
Medicare multiplies 1% of the national base beneficiary premium ($38.99 in 2026) by the number of full months you went without Part D or creditable coverage, then rounds to the nearest $0.10. It applies once you have gone 63 or more days in a row without coverage.
Do I pay a penalty if I had employer coverage?+
No, if the coverage came from current employment (yours or your spouse’s) you can delay Part B and sign up during a Special Enrollment Period within 8 months of the job or coverage ending. Retiree coverage and COBRA do not count for this. Creditable employer drug coverage avoids the Part D penalty.
Does the Medicare late enrollment penalty ever go away?+
The Part B and Part D penalties generally last for as long as you have that coverage. Exceptions include people who qualify for Extra Help (Part D penalty removed) and people under 65 on disability whose penalty ends at 65. The Part A penalty lasts twice the number of years you were late.
Can I appeal a Part D late enrollment penalty?+
Yes. You can ask your drug plan for a reconsideration, usually within 60 days of the letter, if you had creditable coverage, were given incorrect information, or had another qualifying reason. Send proof such as a creditable coverage notice from a former employer.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.