Medicare Late Enrollment Penalty: How Much It Costs and How to Avoid It

A Medicare late enrollment penalty is a surcharge added to your monthly premium when you sign up for Part A, Part B or drug coverage after your first window closes and you had no qualifying coverage in the meantime. It is not a one-time fine. For Part B and Part D it usually lasts as long as you keep that coverage.

Each part has its own formula. Part B adds 10% of the standard premium for every full 12 months you were late. Premium Part A adds a flat 10% for twice the years you waited. Part D adds 1% of a national base premium for every month without creditable drug coverage, and that dollar amount changes every January.

This guide works through the math with the official 2026 numbers, shows how Medicare counts your late months, and covers every way to avoid, shrink or remove a penalty. Every figure was checked against Medicare.gov, CMS, Social Security and the federal regulations on October 27, 2026.

Key Takeaways

• Part B: 10% of the $202.90 standard premium for each full 12 months late, so $20.29 a month per year of delay in 2026, usually for life.
• Part D: 1% of the $38.99 base beneficiary premium for each uncovered month, rounded to the nearest $0.10. The base rises to $41.33 in 2027, so the same penalty grows.
• Premium Part A: a flat 10% ($342.10 instead of $311, or $621.50 instead of $565), paid for twice the number of full years you could have enrolled.
• Extra Help stops the Part D penalty, a Medicare Savings Program generally wipes out the Part B penalty, and people under 65 get a fresh start at 65.
• You can challenge a Part D penalty within 60 days of the date on the letter. Part B and Part A penalties go to Social Security.

What triggers a Medicare late enrollment penalty?

You trigger a penalty by missing your Initial Enrollment Period without coverage Medicare accepts in its place. That window runs seven months, from three months before your 65th birthday month to three months after it. Sign up later without a Special Enrollment Period, and a surcharge follows.

Medicare.gov is blunt about how these charges work. They are “added to your monthly premium,” they are “not a one-time late fee,” and they “go up the longer you wait to sign up,” according to its page on avoiding late enrollment penalties.

The three penalties are independent. You can owe one, two or all three, depending on which parts you delayed and what other coverage you had. Here is how they compare side by side.

Penalty	Rate	Counted in	How long you pay	2026 base
Part B	10% per full 12 months late	Whole years only	Usually as long as you have Part B	$202.90 standard premium
Premium Part A	Flat 10%, never more	Whole years only	Twice the number of full years late	$311 or $565 premium
Part D	1% per uncovered month	Single months, after a 63-day gap	Usually as long as you have drug coverage	$38.99 base beneficiary premium

If you are still deciding when to sign up, our guide to when you can enroll in Medicare lays out every window. The rest of this page is about the money: what a penalty costs and how to get out from under one.

How much is the Part B late enrollment penalty in 2026?

The Part B late enrollment penalty is 10% of the standard Part B premium for each full 12 month period you could have had Part B but did not. With the 2026 standard premium at $202.90, every full year of delay adds $20.29 a month. Two years adds $40.58, five years adds $101.45.

The rule sits in federal regulation 42 CFR 408.22, which says the standard premium “is increased by ten percent for each full twelve months” of late enrollment. Partial years do not count. Eleven months late costs nothing extra, and 23 months costs the same as 12.

Medicare rounds the total monthly premium, penalty included, to the nearest 10 cents. Its own 2026 example: a 24 month delay means a 20% penalty, $202.90 plus $40.58, or $243.48, which becomes a premium of $243.50. The table below applies the same method to other delays.

Full years late	Penalty rate	Added each month	2026 monthly premium	Extra cost per year
1 (12 to 23 months)	10%	$20.29	$223.20	$243.60
2 (24 to 35 months)	20%	$40.58	$243.50	$487.20
3 (36 to 47 months)	30%	$60.87	$263.80	$730.80
5 (60 to 71 months)	50%	$101.45	$304.40	$1,218.00

The penalty is a percentage, so it rides along with the premium. When the standard premium rose from $185.00 in 2025 to $202.90 in 2026, per the CMS 2026 premium fact sheet, every existing Part B penalty grew with it.

Over a long retirement the total adds up. A 20% penalty kept for 20 years at today’s rounded premium is $9,744, and more if premiums keep rising. The 2027 Part B premium has not been announced yet; CMS released the 2026 figure on November 14, 2025, so expect the 2027 number in the late fall.

Higher earners can pay twice. Medicare.gov notes you “may also pay a higher premium depending on your income,” which is the income-related surcharge explained in our IRMAA guide. For the standard premium itself, see our 2026 Part B premium breakdown.

How does Medicare count the months you were late?

For anyone who first enrolls in Part B on or after January 1, 2023, Medicare counts the months from the end of your Initial Enrollment Period through the end of the month you sign up. It then removes months you were covered by an employer plan from current work, plus a few other excluded periods, and divides by 12.

That counting rule is in 42 CFR 408.24(b), which counts “the number of months elapsed between the close of the individual’s initial enrollment period and the close of the month in which he or she first enrolled.” Only full 12 month blocks turn into penalty percentages.

A worked count that shows why timing inside the window matters

Take someone who turned 65 in December 2024 with no job-based coverage. Their Initial Enrollment Period ran from September 2024 through March 2025, so late months start counting in April 2025. They miss the window and plan to use the General Enrollment Period in early 2027.

• Sign up in January 2027: April 2025 through January 2027 is 22 months. That is one full year, so the penalty is 10%.
• Sign up in March 2027: April 2025 through March 2027 is 24 months. That is two full years, so the penalty doubles to 20%.

Both dates are inside the same General Enrollment Period, which runs January 1 to March 31, with coverage starting the month after you sign up, per Social Security. Waiting two months in this example costs an extra $20.29 a month for life at 2026 rates.

So if you are already late, count your months before you pick a date. Signing up early in the window can keep you under the next 12 month line and starts coverage sooner.

Months that do not count against you

Section 408.24 and Social Security’s operating manual remove several kinds of months from the count. The big ones for most readers:

• Months you had employer group coverage based on your own or your spouse’s current work.
• Months of non-coverage covered by an exceptional condition Special Enrollment Period, as long as you enroll before it ends.
• Any months in or before a period when your state paid your Part B premium under a buy-in agreement.
• For people under 65, months before their current stretch of disability entitlement.

The employer months still come off even if you miss your Special Enrollment Period. Social Security’s manual describes a retiree who enrolled late through the General Enrollment Period, yet the months she was covered by a job-based plan “can be excluded from the premium surcharge calculation,” per POMS HI 00805.281.

COBRA and retiree plans are different. Medicare.gov gives you “up to 8 months after you stop working (or lose your health insurance, if that happens first)” to sign up, “whether or not you choose COBRA.”

COBRA “doesn’t extend your limited time to sign up,” Medicare.gov adds. Months on COBRA after that 8 month window count toward a penalty.

Is there a penalty for Part A if you have to buy it?

Yes, but only if you pay a Part A premium. Most people get Part A free after 40 quarters of work and owe no Part A penalty. If you must buy Part A and sign up late, your premium rises a flat 10%, and you pay that higher rate for twice the number of full years you could have enrolled.

Unlike Part B, this surcharge does not stack. Social Security’s manual says the Part A surcharge “is limited by law to 10 percent no matter how late an individual enrolls in the program,” per POMS HI 00805.285. What grows with the delay is how long you pay it.

CMS publishes the penalty rates directly. For 2026, the full $565 premium becomes $621.50 a month with the 10% surcharge, and the reduced $311 premium for people with 30 to 39 quarters becomes $342.10, according to the CMS 2026 rate update.

Months late	Full years counted	Years you pay the 10%	Extra cost at $311 tier (2026 rate)
8	0	None	$0
13	1	2 years (24 months)	$746.40
28	2	4 years (48 months)	$1,492.80
48	4	8 years (96 months)	$2,985.60

The 8, 13 and 28 month counts come from worked examples in 42 CFR 406.33. One of them, enrolled 28 months late, has the increase “eliminated after he has paid the additional 10 percent for 48 months.” The dollar column is our math at the 2026 rate of $31.10 a month extra.

Part A and Part B penalties often travel together for people who buy Part A, because both are tied to the same enrollment windows. Our Part A premium guide explains who pays $311, who pays $565 and who pays nothing.

How is the Part D late enrollment penalty calculated?

Medicare multiplies 1% of the national base beneficiary premium by the number of full months you went without Part D or other creditable drug coverage, then rounds to the nearest 10 cents. For 2026 the base is $38.99, so each uncovered month adds about 39 cents to your monthly premium.

The penalty only applies after a gap of 63 days or more in a row after your Initial Enrollment Period ends, under 42 CFR 423.46. A gap of 62 days or less costs nothing. Once a gap reaches 63 days, every full month of that gap counts.

Medicare’s Part D penalty fact sheet spells out the formula as “1% × national base beneficiary premium × number of full months without Part D or creditable coverage.” Its example is a man who went 17 months uncovered: 17% of $38.99 is $6.63, which rounds to $6.60 a month for 2026.

Uncovered months	Penalty rate	2026 penalty ($38.99 base)	2027 penalty ($41.33 base)
7	7%	$2.70	$2.90
30	30%	$11.70	$12.40
48	48%	$18.70	$19.80
60	60%	$23.40	$24.80

The penalty is added to your plan’s premium, even a $0 premium plan, and it follows you if you switch. Medicare.gov says it “is added for as long as you have Medicare drug coverage, even if you switch plans.” That includes a Medicare Advantage plan that carries drug coverage.

You do not get a bill out of nowhere. When you join a drug plan, the plan checks Medicare’s records for a possible gap and mails you a notice with a form about your past drug coverage. Return it by the deadline printed on it, because this is your first chance to stop a wrong penalty.

For the rest of what drug coverage costs, including the yearly out-of-pocket cap, see our Medicare Part D costs guide.

Why does your Part D penalty change every January?

Your penalty percentage is fixed, but the dollar base is not. Medicare recalculates the national base beneficiary premium every year, then applies your same percentage to the new base. When the base goes up, your penalty goes up, even though you have not missed a single extra month.

CMS set the 2027 base beneficiary premium at $41.33 on July 28, 2026, up from $38.99, per its 2027 Part D bid fact sheet. Someone carrying a 30% penalty pays $11.70 a month in 2026 and $12.40 in 2027.

There is a limit on how fast it climbs for now. CMS says that between 2024 and 2029 the yearly increase in the base beneficiary premium is capped “not to exceed 6% per year.” The 2027 jump is right at that ceiling, so a Part D penalty can rise by up to 6% a year through 2029.

Which penalty grows faster, Part B or Part D?

Part B grows faster in dollars. After five years, Part B adds $101.45 a month in 2026, while Part D adds $23.40. But Part D starts charging as soon as a gap reaches 63 days in a row, and every full month of that gap counts, while Part B charges nothing until a full 12 months have passed.

The chart shows both penalties at 2026 rates. Part B moves in yearly steps; Part D climbs a little every month.

The practical takeaway: if you need to choose, Part B is the more expensive one to put off. Part D is cheaper per month, but it is the one people most often leave for later when they take no prescriptions, and a long gap adds up.

Medicare.gov describes the Part D rate as “an extra 1% for each month (that’s 12% a year).” Someone who skips drug coverage for 10 years would carry a 120% penalty, larger than the base premium itself. Joining a low-cost plan on time is usually cheaper than paying that surcharge for decades.

What counts as creditable drug coverage?

Creditable drug coverage is any drug plan expected to pay, on average, at least as much as standard Medicare drug coverage. Months with creditable coverage do not count toward a Part D penalty. Employer, union and other non-Medicare drug plans must tell you in writing each year whether their coverage is creditable.

CMS names the usual sources on its creditable coverage page: some employer drug coverage including the Federal Employees Health Benefits Program, qualified State Pharmaceutical Assistance Programs, “military-related coverage (e.g., VA, TRICARE)” and “certain Medicare supplemental (Medigap) policies.”

Medicare’s fact sheet adds coverage from a current or former employer or union, the Indian Health Service, and Tribal and Urban Indian programs. The word “some” matters. Not every employer plan qualifies, and the only way to know is the written notice.

Keep those notices in a folder with your Medicare papers. If a drug plan later flags a gap, a creditable coverage letter from each year is the strongest proof you can send. Ask your benefits office for copies now if you never saved them.

Who does not have to pay the Medicare late enrollment penalty?

You generally avoid a penalty if you qualify for a Special Enrollment Period, get Extra Help with drug costs, or enroll in a Medicare Savings Program. People who had job-based coverage from current work, or who were under 65 on disability, also have their late months reduced or reset.

Workers and spouses with job-based coverage

If you or your spouse are still working and covered by that employer’s group plan, you can wait to take Part B. You then get the 8 month Special Enrollment Period after the work or the coverage ends, and Social Security says “there are no penalties if you sign up or add Part B during this time.”

The same logic applies to drug coverage if the employer plan is creditable. Our Medicare enrollment dates guide lists the other Special Enrollment Periods, such as losing Medicaid or getting wrong information from an employer, which also keep penalty months off your record.

Every event that opens one, with its exact window and the forms that prove it, is in our Medicare special enrollment period guide.

People who qualify for Extra Help

Federal rule 42 CFR 423.780(e) is short: people eligible for the Part D low income subsidy “are not subject to a late enrollment penalty.” Medicare’s fact sheet adds that you are not charged the penalty while you get Extra Help.

It also says Medicare “won’t count any months when you didn’t have creditable coverage before you qualified for Extra Help.” If you lose Extra Help later and then have a new gap of 63 days or more, a new penalty can start. Check whether you qualify in our Extra Help guide.

People in a Medicare Savings Program

Medicare.gov says you generally won’t pay a Part B penalty if you “enroll in a Medicare Savings Program.” The reason is in 42 CFR 408.24, which drops months “in or before a period of coverage under a State buy-in agreement” from the count.

In plain terms, once your state starts paying your Part B premium, your earlier late months stop counting.

Income limits for these programs are higher than many people expect. See our Medicare Savings Programs guide for the 2026 limits and how to apply through your state Medicaid office.

People under 65 with a disability

If you got Medicare through SSDI and owe a penalty, turning 65 gives you a new Initial Enrollment Period. Social Security’s manual says the Part B surcharge “will be eliminated since Ken will have a new IEP based on attainment of age 65,” in its example of a disabled beneficiary.

Part D works the same way. CMS guidance for drug plans describes a woman with 12 counted months before 65 who joined a plan in her new enrollment window at 65; her plan resets the count to zero and tells her “she no longer has a penalty.” If you are not in a drug plan at 65, join during that new window.

Readers on disability benefits can find more in our SSDI program guide.

Can a late enrollment penalty be removed after it starts?

Yes, in four main ways. Extra Help stops the Part D penalty. A Medicare Savings Program generally ends the Part B penalty. Turning 65 resets penalties earned on disability Medicare. And if a government error caused the late enrollment, Social Security can grant equitable relief and correct your premium.

Equitable relief is the least known. Social Security’s manual allows it when your enrollment rights were harmed “because of the error, misrepresentation, or inaction of an employee or agent of the Government,” per POMS HI 00805.170. Think of a Social Security worker who told you, wrongly, that you could wait.

Two details help you. There is “no time limitation on granting relief,” so an old mistake can still be fixed. And where the government “clearly erred,” staff should consider relief on their own, without you asking. Still, ask in writing and include names, dates and what you were told.

Equitable relief does not cover mistakes by a private employer or an insurance agent. For those, the exceptional condition Special Enrollment Period for employer or plan misinformation is the route, and months it covers drop out of the penalty count under 42 CFR 408.24(b)(2).

The penalty does not end just because you switch plans or move. A Part D penalty follows you to any new drug plan, and a Part B penalty stays with your Part B. Dropping coverage to escape a penalty only makes the next one bigger.

How do you appeal a Part D late enrollment penalty?

Use the reconsideration form your drug plan sent with the penalty notice. Return it to the address or fax number on the form within 60 days of the date on the letter, along with proof of creditable coverage. A Medicare contractor that is not part of your plan makes the decision, usually within 90 days.

Here is the process step by step, based on Medicare’s Part D penalty fact sheet:

1. Find the late enrollment penalty notice and the reconsideration form inside it.
2. Gather proof for each disputed month, such as creditable coverage letters, plan ID cards, or an Extra Help award letter.
3. Fill out the form and send it, with copies of your proof, within 60 days of the date printed on the letter.
4. If you are late, explain why in writing. Medicare says you must explain why your form is late.
5. Keep paying the penalty with your premium while you wait. Plans can disenroll you for unpaid premiums, and the penalty counts as premium.
6. Watch for the decision letter, usually within 90 days. The contractor can take 14 more days if you ask for time or it needs more information.

If the contractor agrees with you, your plan removes or lowers the penalty, tells you the correct premium and explains any refund for what you paid during the review. If it disagrees, you keep paying.

There is no further appeal in the usual sense. Under 42 CFR 423.46(c), these decisions “are not subject to appeal, but may be reviewed and revised at the discretion of CMS.” That makes the first request your best shot, so send complete proof the first time.

One common reason does not work. Medicare says joining a different plan “generally won’t give you a reason to ask for a reconsideration” if you already pay the penalty.

How do you challenge a Part B or Part A penalty?

Part B and premium Part A penalties are Social Security decisions, so you ask Social Security to reconsider. You can file a non-medical reconsideration online, or send Form SSA-561 to your local office. Use the appeal deadline printed on the notice that set your premium.

Social Security’s Form SSA-561 page links the online non-medical appeal and the paper form. You can also call 1-800-772-1213 for help. Include evidence that removes months from the count.

The strongest evidence is proof of employer group coverage based on current work for the months in question. A letter from each employer’s benefits office showing coverage dates is the usual starting point. Bring it to Social Security with your Medicare card and the penalty notice.

If the late enrollment traces back to a mistake by Social Security or another government office, ask for equitable relief in the same request. If an employer or plan misled you, ask about the exceptional condition Special Enrollment Period for employer or plan misinformation instead.

For help preparing either kind of request, free counseling is available through your State Health Insurance Assistance Program at shiphelp.org.

What should you do if you are close to a deadline right now?

Count your months first, then act early inside any window you have. A few weeks can move you across a 12 month line for Part B or add months to a Part D gap. If you are already in a General Enrollment Period, signing up in January rather than March can lower the penalty.

• Turning 65 within three months: enroll in Part B and a drug plan now unless job-based coverage from current work covers you.
• Leaving a job or losing job coverage: mark the date. Your 8 month Special Enrollment Period starts then, even if you take COBRA.
• No drug coverage at all: Open Enrollment runs October 15 to December 7, and a plan you join in that window starts January 1. Every uncovered month until then still adds 1%, so do not skip another year.
• Low income: apply for Extra Help and a Medicare Savings Program. Both can erase penalties you already have.
• Penalty notice in hand: note the date on the letter. For Part D you have 60 days from that date to file.

The Medicare open enrollment guide covers the fall window in detail, and the Medicare program overview pulls the cost pages together in one place.

Related reading

• 2026 Medicare Part B premium and IRMAA brackets
• Medicare Part D costs, premiums and the out-of-pocket cap
• Help paying Medicare costs on a low income
• Medicare Advantage vs Original Medicare