Medicare Part B Penalty Calculator
Find out exactly how much the Part B late enrollment penalty adds to your monthly premium — permanently — and what it means for San Diego residents turning 65.
Calculate Your Penalty
Enter the month you first became eligible for Part B and the month you actually enrolled. The calculator determines how many full 12-month periods you delayed.
* Estimate uses the 2025 standard Part B premium of $185.00/month. This tool is for educational purposes only and may not reflect your exact penalty. Contact Medicare or a licensed broker to confirm.
What Is the Part B Late Enrollment Penalty?
Medicare Part B covers doctor visits, outpatient care, preventive services, and medical equipment. Most people pay a monthly premium for it. If you don't sign up when you're first eligible — and you don't have qualifying employer coverage — Medicare adds a permanent penalty to your premium.
The penalty is 10% of the standard Part B premium for each full 12-month period you were eligible but didn't enroll. Unlike Part D, the penalty is calculated in full-year increments, not month by month.
The Formula
Only full 12-month periods count. An 11-month delay = 0 penalty periods. A 13-month delay = 1 penalty period (10%).
Example — 2.5 Year Delay
How to Avoid the Penalty
- ✓Enroll during your Initial Enrollment Period — starting 3 months before the month you turn 65
- ✓If you have active employer coverage (yours or a spouse's), you can delay without penalty — but enroll within 8 months of losing that coverage
- ✓Retiree coverage, COBRA, and marketplace plans do NOT protect you from the penalty
- ✓Contact Ashley to review your situation before your IEP window closes
Also worried about Part D?
Part D (drug coverage) has its own separate late enrollment penalty.
Use the Part D Penalty CalculatorCommon Part B Penalty Questions
Who is exempt from the Part B penalty?
You're exempt if you had coverage through an employer or union based on active employment (yours or your spouse's) when you first became eligible. Once that coverage ends, you get a Special Enrollment Period of 8 months to sign up without penalty. Retiree coverage, COBRA, or marketplace plans do NOT count — only active employment coverage.
When does the Part B penalty clock start?
The clock starts the month after your Initial Enrollment Period ends — typically 3 months after you turn 65. If you're delaying because of active employer coverage, the clock doesn't start until that coverage ends.
How long do I pay the Part B penalty?
For as long as you have Medicare Part B — the penalty never goes away. That's why enrolling on time is so important. A 2-year delay means a 20% higher premium for the rest of your life.
Does the penalty dollar amount stay the same?
No — the penalty percentage stays fixed (e.g., 20% for a 2-year delay), but because it's applied to the standard Part B premium, the dollar amount changes each year when CMS adjusts the premium.
Can I appeal the Part B penalty?
Yes, in certain circumstances — for example, if you were given incorrect information by a federal employee, or if you had creditable employer coverage that wasn't properly documented. Ashley can help you understand whether an appeal or Equitable Relief request makes sense for your situation.