Enter your first Part B eligibility month and your enrollment month, then check to estimate any 2026 late enrollment penalty.
About the Medicare Part B late enrollment penalty checker
The Medicare Part B late enrollment penalty checker estimates the lifetime surcharge you could owe if you delayed Part B without qualifying coverage. Enter the month your Part B eligibility began, the month you enrolled or plan to enroll, and whether you had health coverage from current employment, and it estimates the penalty percent, the monthly amount added to the 2026 standard premium, and the yearly cost.
The Part B late enrollment penalty adds 10% to the standard premium for each full 12-month period you could have signed up for Part B but did not, and it generally lasts for as long as you have Part B. Medicare counts the months from the end of your Initial Enrollment Period, and the Social Security Administration determines the amount you actually owe. This tool is informational only and is not financial, tax, or medical advice. Confirm your situation with Medicare and Social Security.
How to use
- Enter the month your Part B eligibility began, which is usually the month your Initial Enrollment Period started around age 65.
- Enter the month you enrolled in Part B, or the month you plan to enroll.
- Check the box if you had health coverage from current employment (yours or your spouse's) during the gap, which usually means a Special Enrollment Period and no penalty.
- Select Check penalty to see the estimated penalty percent, the monthly amount added to the standard premium, and the yearly cost.
- Confirm your own enrollment periods and penalty with Medicare and the Social Security Administration, since they set the official amount.
Worked examples
Eligible January 2022, enrolled January 2024, no employer coverage
Two full 12-month periods late means about a 20% penalty, roughly $40.58 added per month on top of the 2026 standard premium for as long as you have Part B.
Eligible January 2024, enrolled June 2024
Five months late is under one full 12-month period, so there is no penalty yet because the penalty is assessed per full 12-month period.
Late enrollment but covered by a current employer plan
Qualifying coverage from current employment generally grants a Special Enrollment Period, so no penalty applies when you enroll within the allowed window.
Frequently asked questions
- How is the Part B late enrollment penalty calculated?
- The penalty adds 10% to the standard Part B premium for each full 12-month period you could have had Part B but did not sign up. For example, two full years late is a 20% penalty added to the standard premium.
- How long does the penalty last?
- For most people the Part B late enrollment penalty lasts for as long as they have Part B. It is added to the monthly premium each year, and because it is a percentage of the standard premium it can change as that premium changes.
- Does coverage from my job avoid the penalty?
- Generally yes. If you had group health coverage from current employment, your own or a spouse's, you usually qualify for a Special Enrollment Period and can enroll without a penalty. COBRA and retiree coverage do not count, and you generally must enroll within 8 months of the employment coverage ending.
- What premium is the penalty based on?
- The estimate uses the 2026 standard Part B monthly premium of $202.90. Medicare rounds the resulting monthly amount to the nearest 10 cents. Your actual premium may also be higher based on income through a separate IRMAA surcharge.
- Is this tool financial or medical advice?
- No. This is a free informational estimate based on the months you enter and the published 2026 standard premium. It does not determine your official penalty, enrollment periods, or eligibility, which are set by Medicare and the Social Security Administration.
- Do you store the dates I enter?
- No. The estimate runs entirely in your browser, and the months you enter are not saved or sent to a server.
- Is the Medicare Part B penalty checker free?
- Yes. It is free to use and does not require an account.
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