Medicare Late Enrollment Penalties: How Part A, B, and D Penalties Work — and How to Fix One

Medicare has enrollment windows, and it enforces them with penalties designed to last. Some people miss theirs because no one told them a window existed. Others assume — reasonably, but incorrectly — that keeping other coverage is enough to put off signing up. Either way, the penalties are calculated automatically, they rarely get waived, and two of the three compound for as long as you're on Medicare. Here's how each one actually works, who's exempt, and what you can still do if you're already paying one.

Medicare's late enrollment penalties exist to keep the risk pool stable. If people could wait until they got sick to sign up for Part B or a drug plan, premiums for everyone else would rise, because only the people who needed care right away would be paying in. The penalty is the trade-off for that guarantee — Medicare has to take you regardless of health, so it charges more to anyone who waited without a qualifying reason.

That logic explains why the penalties are permanent rather than one-time fees, and why "I didn't know" doesn't usually excuse it. It also means the fix, in almost every case, is prevention: knowing your window before you reach it.

If you don't sign up for Part B when you're first eligible — and you don't have coverage through current, active employment that qualifies as creditable — the penalty is 10% of the standard Part B premium for every full 12-month period you could have had Part B but didn't. The standard Part B premium in 2026 is $202.90 a month, and this penalty is added to your premium for as long as you're enrolled in Part B. It does not expire.

The math compounds fast. Someone who waits three full years pays a permanent 30% surcharge; five years is 50%. Unlike IRMAA, which is income-based and can change year to year, the Part B late enrollment penalty is fixed to how long you delayed and doesn't go away when your income does.

If you go 63 or more consecutive days without Part D or other creditable prescription drug coverage after your Initial Enrollment Period ends, you'll owe a Part D late enrollment penalty once you do sign up. It's calculated as 1% of the national base beneficiary premium, multiplied by the number of full months you went without creditable coverage. The national base beneficiary premium for 2026 is $38.99.

Like the Part B penalty, this one is added to your premium for as long as you're enrolled in a Medicare drug plan — it doesn't reset if you switch plans during Open Enrollment, and it recalculates upward slightly each year as the base premium changes.

Most people don't pay a premium for Part A at all — it's earned through work history (yours or a spouse's), so there's nothing to be late on. The Part A penalty only applies to the minority who have to buy Part A because they don't have enough work credits. If that's you and you delay enrolling, the penalty is a 10% surcharge on the Part A premium, and unlike Parts B and D, it's not for life — you pay it for twice the number of years you were eligible but didn't enroll, then it drops off.

The penalties exist for people who had no qualifying reason to wait. A few groups genuinely do:

• Active employer or union group coverage. If you or your spouse are still working and covered under a current employer's plan of 20 or more employees, you can delay Part B penalty-free. You get an 8-month Special Enrollment Period once that employment or the coverage ends — whichever comes first — to sign up without a penalty. Retiree coverage and COBRA do not count for this purpose, which is the single most common mistake people make.
• Extra Help (Low-Income Subsidy) recipients. If you qualify for Extra Help, you never owe the Part D late enrollment penalty — and if you already have one when you qualify, it's waived while you have Extra Help.
• VA or TRICARE coverage can also serve as creditable drug coverage, depending on your specific benefit — verify the "creditable coverage" notice rather than assuming.

If you didn't sign up for Part B when you were first eligible and don't qualify for a Special Enrollment Period, your next chance is the General Enrollment Period, January 1 through March 31 each year. Under the BENES Act, coverage now starts the first day of the month after you enroll — a real improvement over the old rule, which could leave people waiting until July 1 with a gap in coverage. The penalty still applies once you enroll; the GEP just gets you back into the system without an indefinite wait.

Neither penalty is automatically permanent if the reason you missed your window was Medicare's fault, or if you were given wrong information by an employer, insurer, or government agency. The two appeal paths are different:

• Part B penalty ("equitable relief"): Contact Social Security directly and request a review, explaining in writing what happened — for example, being told incorrectly that COBRA or retiree coverage let you delay. There's no standard form; it's a written explanation and supporting documentation reviewed on a case-by-case basis.
• Part D penalty (formal reconsideration): You have 60 days from the notice of your penalty to file a reconsideration request with C2C Innovative Solutions, the independent review entity under contract with Medicare for these appeals. They generally decide within 90 days, and the form comes with your penalty notice or is available through Medicare.

Appeals succeed most often when there's a paper trail — a letter from an employer's HR department, an insurer's own creditable-coverage notice, or written correspondence that shows you were misinformed. Verbal assurances alone rarely carry the case.

Medicare's late enrollment penalties aren't designed to be punitive so much as permanent — which makes them far more expensive than they look on paper. A 20% Part B surcharge or a few dollars a month on Part D doesn't sound like much until you multiply it across the rest of your life on Medicare.

The good news is that every one of these penalties is avoidable with the right timing, and even an existing one isn't always the final word. Know your enrollment window, confirm your other coverage actually qualifies as creditable, and if something was calculated wrong, ask for a review. The forms exist for a reason.

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