Medicare Late Enrollment Penalty Calculator: Part B & Part D (2026)
Quick answer: Medicare charges a penalty if you sign up for Part B or Part D late without other creditable coverage. In 2026, Part B adds 10% of the $202.90 premium for each full year you waited, and Part D adds 1% of the $38.99 base premium for each full month. Both penalties are permanent.
This free Medicare late enrollment penalty calculator shows what a late sign-up costs every month, every year, and over the long run. Enter the months you went without Part B or Part D, and it works out each penalty separately, then adds them together. The Part B penalty is 10% of the standard premium for each full year you waited. The Part D penalty is 1% of the national base premium for each full month you went without drug coverage. Both penalties last as long as you have that part of Medicare, which for most people means for life, so a delay of a year or two can cost thousands of dollars over time.
Medicare Late Enrollment Penalty Calculator
2026 figures from the Centers for Medicare and Medicaid Services and Medicare.gov. Your numbers stay in your browser.
Count from the end of your 7-month Initial Enrollment Period until the month your Part B started. Enter 0 if you signed up on time.
Months on a current employer's group plan do not count toward the penalty. COBRA and retiree coverage do not count here, so do not include them.
Count only full months. A partial month at either end does not count.
The Part D penalty only starts after 63 straight days without Part D or other creditable drug coverage. Untick this box if no single gap ever reached 63 days.
Private by design: this tool runs entirely in your browser. The numbers you type never leave your device and are never stored. Close the page and they are gone.
Estimate only. Social Security makes the official Part B determination, and your Part D plan makes the official Part D determination. 2026 figures: Part B $202.90 a month, Part D base $38.99 a month. Yearly figures are the monthly penalty times 12; the billed yearly total can differ by a few dollars because the monthly bill rounds the total premium to the nearest 10 cents.
How the Part B Penalty Works
What is the Medicare late enrollment penalty, in one line? It is the extra amount Medicare adds to your monthly premium when you sign up late without other creditable coverage. For Part B, the rule is 10% of the standard Part B premium for each full 12-month period you could have had Part B but did not. The standard premium in 2026 is $202.90 a month, up $17.90 from $185.00 in 2025. One year late adds $20.29 a month; two years adds $40.58 a month. This page is your Part B penalty calculator: enter your months late above.
Only full years count. Eleven months late costs nothing. Twelve months late costs 10%. Twenty-three months late still costs 10%. Twenty-four months late costs 20%. Leftover months never count.
The Medicare Part B penalty 10% per year is permanent: Medicare.gov says the extra amount is usually charged for as long as you have Part B, which for most people means for life. The dollar amount does change over time, because it is recalculated whenever the standard premium changes. The penalty is figured on the standard premium, not on your total premium, so if you also pay IRMAA for higher income, the penalty is still figured on $202.90 and the IRMAA is added on top. Our IRMAA Estimator checks it separately.
Medicare.gov gives its own worked example: "If you waited 2 full years (24 months) to sign up for Part B, but you did not have creditable coverage during that time, you will have to pay a 20% late enrollment penalty. $202.90 + $40.58 = $243.48. $243.50 will be your Part B monthly premium for 2026." The premium is rounded to the nearest 10 cents, so $243.48 becomes $243.50 on the bill.
Part B penalty by length of delay, 2026 figures
| Months late | Penalty | Penalty per month | Total Part B per month |
|---|---|---|---|
| 0 to 11 | 0% | $0.00 | $202.90 |
| 12 to 23 | 10% | $20.29 | $223.20 |
| 24 to 35 | 20% | $40.58 | $243.50 |
| 36 to 47 | 30% | $60.87 | $263.80 |
| 48 to 59 | 40% | $81.16 | $284.10 |
| 60 to 71 | 50% | $101.45 | $304.40 |
One note on yearly figures: the annual amounts on this page multiply the monthly penalty by 12. Your Part B bill rounds the total premium to the nearest 10 cents, so the amount actually billed over a year can differ by a few dollars from the penalty multiplied by 12.
Five years late is the starkest row: $101.45 extra every month, $1,217.40 extra every year, for as long as you have Part B. Held at 2026 premiums, that is about $12,174 over 10 years. Premiums usually rise, so the real lifetime cost is higher. That is an illustration, not a forecast.
How the Part D Penalty Works
The Medicare Part D penalty 1% per month is figured on the national base beneficiary premium, which is $38.99 a month in 2026. This page works as a Part D late enrollment penalty calculator too: one month without drug coverage adds about $0.40 a month after rounding. Twelve months adds $4.70 a month, fourteen months $5.50, and twenty-four months $9.40. The penalty is rounded to the nearest 10 cents and added to your drug plan premium every month.
Two gates decide whether any Part D penalty applies at all. The first is the 63-day rule: the penalty only starts if you go 63 days or more in a row without Part D or other creditable drug coverage after your Initial Enrollment Period ends. A gap of 62 days costs nothing. The second gate is the full-month rule: only whole months count, so two months and three weeks without coverage is two months for penalty purposes, not three.
Like the Part B penalty, the Part D penalty is permanent: Medicare.gov says it is added for as long as you have Medicare drug coverage, even if you switch plans. Changing to a cheaper plan lowers your plan premium, but the penalty follows you. The amount is recalculated yearly from the base premium.
Medicare.gov gives its own worked example for Part D as well: a person who went 14 months without Part D or creditable coverage pays a 14% penalty, and "$38.99 x 0.14 = $5.46 (rounded to the nearest $0.10 = $5.50). $5.50 will be your monthly penalty for 2026."
Part D penalty by length of delay, 2026 figures
| Full months without drug coverage | Penalty | Penalty per month | Extra per year |
|---|---|---|---|
| 1 | 1% | $0.40 | $4.80 |
| 12 | 12% | $4.70 | $56.40 |
| 14 | 14% | $5.50 | $66.00 |
| 17 | 17% | $6.60 | $79.20 |
| 24 | 24% | $9.40 | $112.80 |
| 29 | 29% | $11.30 | $135.60 |
| 36 | 36% | $14.00 | $168.00 |
| 60 | 60% | $23.40 | $280.80 |
How much is the Medicare late enrollment penalty when both parts are late? The two penalties stack. Someone 24 months late on both parts in 2026 pays $40.58 for Part B plus $9.40 for Part D, or $49.98 extra every month, which is $599.76 extra every year. One figure to be careful with: $36.78 is the 2025 Part D base premium, not the 2026 figure. The Centers for Medicare and Medicaid Services set the 2026 base premium at $38.99.
What About the Part A Penalty?
Part A, hospital insurance, has its own late enrollment penalty, but it reaches far fewer people. Most people get premium-free Part A because they or their spouse paid Medicare taxes for 40 quarters, or 10 years, of work. If you must buy Part A and you delay signing up, your monthly premium rises by 10%, and you pay the higher premium for twice the number of years you delayed. Unlike the Part B and Part D penalties, the Part A penalty ends. The 2026 Part A premiums are $565 a month for the full premium (under 30 quarters) and $311 a month for the reduced premium (30 to 39 quarters).
The Three Enrollment Windows
Every penalty story starts with a missed window. Knowing which one applies to you is the difference between a penalty and no penalty.
| Window | When it runs | What happens |
|---|---|---|
| Initial Enrollment Period | 7 months around your 65th birthday | No penalty. Coverage starts the month you turn 65, or the next month. |
| General Enrollment Period | January 1 to March 31 each year | For people who missed their first window. Coverage starts the month after you sign up. A penalty may apply. |
| Special Enrollment Period (employment) | 8 months after the job or group plan ends, whichever is first | For people who delayed Part B for a group health plan through a current employer. No penalty inside it. |
Two details catch people out. First, General Enrollment Period coverage now starts the month after you sign up. Older advice still says July 1, but that was the rule before 2023. Second, the Special Enrollment Period is 8 months from when employment or the group plan ends, not 8 months after COBRA ends. Part D has its own Special Enrollment Period for people who involuntarily lose creditable drug coverage: under the Centers for Medicare and Medicaid Services enrollment guidance, it ends two calendar months after the loss or the notice, whichever is later. Our guide to the creditable coverage letter explains the yearly letter.
What Counts as Creditable Coverage
Creditable coverage protects you from the penalty while you delay Medicare, but Part B and Part D define it differently, and mixing the two definitions up is how most penalties happen.
For Part B: a group health plan through current employment
For Part B, creditable coverage means a group health plan through a current employer, yours or your spouse's. The word current does all the work: while you or your spouse is actively working under that employer's group plan, the Part B clock does not run. When the job or the plan ends, the 8-month Special Enrollment Period starts. COBRA, retiree coverage, and Marketplace plans do not count: Medicare.gov lists all three as situations that do not qualify for a Special Enrollment Period.
This is the COBRA trap, the most common penalty story. A person retires at 66, takes COBRA for 18 months, then signs up for Part B at 67 and learns the 18 COBRA months count as uncovered, a 10% penalty for life. Sign up for Part B in the 8 months after the job or the group plan ends, before COBRA runs out.
For Part D: drug coverage at least as good as Part D
For Part D, creditable coverage means drug coverage whose value equals or exceeds the standard Part D benefit, so your plan is expected to pay, on average, at least as much as Medicare's standard drug benefit. The plan decides whether its coverage meets that standard and must tell you in writing every year, before October 15. If it says creditable, your time on that plan does not count toward the penalty. If it says non-creditable, the 63-day clock is already running, and you should join a Part D plan promptly. Creditable drug coverage can come from an employer or union plan, TRICARE, the Department of Veterans Affairs, or the Indian Health Service. Discount cards, free clinics, and drug samples are not coverage at all. For 2026, a plan must be designed to pay at least 72% of participants' drug expenses to count as creditable under the revised simplified method, up from 60%.
Note the asymmetry: a retiree drug plan can be creditable for Part D even though retiree health coverage does not protect Part B, so check both parts separately.
What to Do If You Are Already Late
The Medicare penalty for signing up late feels unfair when the rules were never explained at 65. But there are still moves that help. First, check whether a Special Enrollment Period still applies to you. If you delayed Part B for a group health plan through a current employer, you have 8 months after the job or the plan ends. If you involuntarily lost creditable drug coverage, you generally have two calendar months after the loss or the notice, whichever is later. If you are unsure, call 1-800-MEDICARE (1-800-633-4227) or ask your local SHIP counselor.
Second, if no Special Enrollment Period applies, use the General Enrollment Period, January 1 to March 31. Coverage starts the month after you sign up. Third, check whether Extra Help or a Medicare Savings Program can waive the penalty. Extra Help is the low-income subsidy for Part D, and while you receive it, you pay no Part D penalty. Our guide to the Extra Help and Medicare Savings Program letter explains who qualifies.
Fourth, if you believe a Part D penalty was charged in error, there is a reconsideration route: penalties are sometimes charged when creditable coverage proof was never matched to the record. The steps are set out in our guide to the creditable coverage letter. Keep every letter and a note of every call, with the date and the name of the person you spoke to. Finally, watch for the scams around enrollment season. Open enrollment runs October 15 to December 7, and it brings calls and letters promising to fix your penalty, lower your premium, or replace your Medicare card for a fee. Medicare will never call and demand payment by gift card, wire, or crypto, and it will never charge a fee to fix a penalty. Our guides to Medicare open enrollment scams and the new Medicare card list the pitches to ignore.
2026 Figures, and What Changes in 2027
Every figure on this page is a Medicare late enrollment penalty 2026 figure, verified against Centers for Medicare and Medicaid Services and Medicare.gov sources on November 3, 2026. The figures are: Part B $202.90 a month, Part D base $38.99 a month, Part A $565 full and $311 reduced. The rules do not change year to year, but the dollar amounts do.
The 2027 Part B standard premium has not been announced yet; the Centers for Medicare and Medicaid Services normally announces it in late November, and this page will be updated then. Do not plan on any 2027 Part B figure quoted before then: projections are not final figures. The 2027 Part D base premium has been published at $41.33 a month. At that figure, the same 14-month gap that costs $5.50 a month in 2026 would cost $5.80 a month in 2027, and a 24-month gap would cost $9.90 a month instead of $9.40. Re-check this page in late November 2026, when the 2027 Part B premium is announced.
Medicare Penalty Questions, Answered
Is the Medicare late enrollment penalty permanent?
Yes, for Part B and Part D. The penalty stays on your premium for as long as you have that part of Medicare, which for most people means for life. The dollar amount changes when the standard premium changes, because the penalty is a percentage of it, but the percentage never drops. The Part A penalty is different: it lasts for twice the number of years you delayed, then ends.
Does IRMAA change my penalty?
No. The late enrollment penalty is figured on the standard Part B premium of $202.90 a month in 2026, or on the Part D base premium of $38.99 a month. IRMAA, the income surcharge for higher incomes, is added on top of the standard premium separately. The two charges stack, so a person can owe both a penalty and IRMAA at the same time. Use our free IRMAA Estimator to check the surcharge for your income.
I worked past 65. Do I owe a penalty?
Not if you had a group health plan through a current employer, yours or your spouse's, while you delayed Part B. That coverage stops the Part B clock, and you get an 8-month Special Enrollment Period after the job or the plan ends. But COBRA and retiree coverage do not count, and a Marketplace plan does not count either. If your only coverage after 65 was COBRA or retiree coverage, the Part B clock was running.
Does COBRA protect me from the penalty?
No, not for Part B. COBRA is continuation coverage from a former employer, and Medicare does not treat it as a group health plan through a current employer. Months on COBRA count as uncovered for Part B, and the end of COBRA does not start a new Special Enrollment Period. For Part D, COBRA drug coverage can be creditable if the plan says so in its yearly letter, so check the letter before you assume the worst.
What if my gap was under 63 days?
Then no Part D penalty applies for that gap. The Part D penalty only starts after 63 days or more in a row without Part D or other creditable drug coverage. A gap of 62 days costs nothing, even if it crosses a month boundary. Part B has no 63-day rule: its penalty counts full 12-month periods, so 11 months late on Part B costs nothing, and 12 months late costs 10%.
Can I appeal a Part D penalty?
Yes. If you believe a Part D penalty was charged in error, for example because you had creditable drug coverage that was never matched to your record, you can ask for reconsideration. Our guide to the creditable coverage letter explains the route and what proof the reviewer will ask for, including the yearly letter from your plan. Keep every letter and a note of every call, with the date and the name of the person you spoke to.
How much is the penalty if I am 2 years late in 2026?
Two years late on Part B means a 20% penalty, or $40.58 a month, for a total Part B premium of $243.50 a month. Two years late on Part D means a 24% penalty, or $9.40 a month. Late on both parts, the combined penalty is $49.98 a month, or $599.76 a year, for as long as you have both coverages. Use the calculator above for your own delay, since 23 months late costs half as much on Part B as 24 months late.
Sources
Figures on this page come from Medicare.gov: Avoid late enrollment penalties (including the worked examples for 24 months late on Part B and 14 months late on Part D); Medicare.gov: When does Medicare coverage start?; the CMS fact sheet on 2026 Medicare Parts A and B premiums and deductibles (November 14, 2025); the CMS fact sheet on 2026 Medicare Part D bid information (July 28, 2025), which sets the base premium at $38.99; CMS: What is creditable coverage?; the CMS Medicare Overview job aid (July 2026); and the CMS annual release of Part D national average bid amounts (July 28, 2025). The two-month Special Enrollment Period after losing creditable drug coverage is in the CMS Medicare Advantage and Part D Enrollment and Disenrollment Guidance, section 30.6.17.
If a letter about your Medicare premium looks wrong, or a caller demands payment to fix it, run the letter through our Letter Explainer first. Medicare will never call and demand payment by gift card, wire, or crypto.