Free Tool · Updated for 2026

Medicare Part B Late Enrollment Penalty Calculator

Enter how many months you delayed (or plan to delay) Part B enrollment. See the monthly, annual, and estimated lifetime cost of the penalty.

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How Much Would A Part B Late Penalty Cost You?

Missing your Initial Enrollment Period triggers a permanent Part B late enrollment penalty. The penalty is 10% of the standard premium for every full 12 months you delayed, added to your premium for life. See what it could cost.

How many months will you have delayed enrollment?

Based on 2026 standard Part B premium of $202.90/month

How The Part B Penalty Works

Medicare charges a late enrollment penalty when you sign up for Part B after your Initial Enrollment Period ends and you didn't have creditable coverage in the meantime. The rules:

The penalty is 10% of the standard Part B premium for each full 12-month period you could have had Part B but didn't
It's added to your premium every month, for as long as you have Part B
The 2026 standard premium is $202.90/month, so each 10% increment adds $20.29/month at today's rate
Because the penalty is a percentage, it grows every time the standard premium rises

Partial years don't count. An 11-month delay carries no penalty. A 12-month delay adds 10%. A 25-month delay adds 20%.

Worked Examples At The 2026 Premium

Delay	Penalty	Added per month	Added per year	20-year estimate
12 months	+10%	$20.29	$243.48	$4,870
24 months	+20%	$40.58	$486.96	$9,739
36 months	+30%	$60.87	$730.44	$14,609
60 months	+50%	$101.45	$1,217.40	$24,348

These estimates hold the premium at the 2026 level. Real lifetime cost runs higher because the standard premium rises most years and the penalty percentage rides on top of it.

How To Avoid The Penalty

Enroll during your Initial Enrollment Period

Your IEP runs from 3 months before your 65th birthday month through 3 months after. Enrolling anywhere in that window means no penalty.

Keep creditable employer coverage

If you or your spouse actively work for an employer with 20+ employees and you're on that group plan, you can delay Part B penalty-free. Get the creditable status confirmed by HR in writing.

Use your Special Enrollment Period when work coverage ends

When employer coverage ends, you get an 8-month Special Enrollment Period to pick up Part B with no penalty. Don't wait: COBRA does not extend this window.

Know what doesn't count

COBRA, retiree plans, VA coverage alone, and individual marketplace plans are not creditable for Part B. People get caught by this every year.

Part B Penalty Questions

How is the Part B late enrollment penalty calculated?

The penalty is 10% of the standard Part B premium for each full 12-month period you delayed enrollment without creditable coverage. A 26-month delay counts as two full 12-month periods, so the penalty is 20%.

How long do I pay the Part B penalty?

For as long as you have Part B. In most cases that means for the rest of your life. The penalty percentage stays fixed, but the dollar amount grows as the standard premium rises each year.

What counts as creditable coverage for Part B?

Group health coverage from an employer with 20 or more employees, based on your or your spouse's current employment. COBRA and retiree coverage do NOT count as creditable for Part B.

Can the Part B penalty be removed or appealed?

Sometimes. If you delayed because you had creditable employer coverage, Social Security uses form CMS-L564 to verify it and waive the penalty. If you received bad advice from a federal employee, equitable relief may apply. An agent can help you sort out which situation you're in.

Is there also a Part D late enrollment penalty?

Yes, and it works differently. The Part D penalty is 1% of the national base premium per month delayed, also added for life. It applies if you go 63 or more days without creditable drug coverage after your IEP.

Does the penalty apply if I delay Part A?

Premium-free Part A has no penalty for most people. If you have to pay for Part A (fewer than 40 work quarters), a late enrollment penalty of 10% can apply for twice the number of years you delayed.

Adam

Licensed Kansas Agent · AHIP Certified

Lawrence native · Free State HS · BS Finance, KU

Talk With Adam. No Pressure, No Cost.

I grew up in Lawrence, graduated from Free State High School, and earned a BS in Finance from the University of Kansas. Most of the people I help are turning 65 or reviewing their current Medicare coverage.

No pressure, no sales pitch. Just clear answers when you're ready to talk.

(785) 843-0288

Medicare Part B Late Enrollment Penalty Calculator

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How The Part B Penalty Works

Worked Examples At The 2026 Premium

How To Avoid The Penalty

Part B Penalty Questions

Talk With Adam. No Pressure, No Cost.

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