Medicare Part B Late Enrollment Penalty Calculator
If you didn’t sign up for Medicare Part B on time, use this free Part B penalty calculator to estimate your cost: Enter the number of months you went without coverage, and you’ll see your estimated monthly penalty right away.
Your monthly total cost is determined by your Part B premium plus the Part B premium penalty. For our calculator, we used $202.90.
However, your Part B premium may be higher if you make more money, or may be lower if you have a Medicare Advantage plan with Part B giveback.
This tool offers an estimate only and may not be accurate for your situation. To learn more about the Part B penalty and potential ways to avoid this penalty, contact me.
How the Part B Penalty Works
If you didn’t enroll in Part B when you were first eligible and didn’t have qualifying coverage through an employer, you may owe a late enrollment penalty that’s added to your monthly premium.
The Medicare Part B late enrollment penalty is permanent. It lasts for as long as you have Part B.
The Medicare Part B penalty increases your premium by 10% for each year (or full 12-month period) you could have had Part B but didn’t.
Here’s a quick 2026 summary chart of how much you pay per year missed:
Time without coverage | Penalty Percent | Penalty Dollar/Month |
Less than one year | 0% | $0 |
12 months to 23 months | 10% | $20.29 |
24 months to 35 months | 20% | $40.58 |
36 months to 47 months | 30% | $60.87 |
48 months to 59 months | 40% | $81.16 |
60 months to 72 months | 50% | $101.45 |
Because this surcharge lasts for as long as you have Part B, even a short delay can add up to thousands of dollars very quickly.
*This tool is an estimate only and may not be exact.
Part B Penalty Explained
The Part B penalty is calculated by taking 10% of the monthly Part B premium and multiplying it by the number of 12 months periods someone has gone without creditable health insurance coverage.