When it comes to enrolling in Medicare, timing is everything. Generally speaking, unless you have another source of qualifying coverage or you meet the criteria for an exception, you should sign up for Medicare when you turn 65. Otherwise, you could face Medicare late enrollment penalties. These surcharges are tacked on to your monthly premiums and can add up over time.
In this article, we’ll take a closer look at late enrollment penalties for not signing up for Medicare Part A (hospital insurance), Part B (medical insurance) and Part D (prescription drug coverage) and how to avoid them. We’ll also discuss when you can enroll in Medicare Advantage plans.
Medicare Part A late enrollment penalty
If you or your spouse paid Medicare taxes for at least 10 years, you may qualify for premium-free Medicare Part A. Being eligible doesn’t always mean you’re automatically enrolled, so you may need to sign up. If you qualify for premium-free Part A, you usually don’t have a late enrollment penalty for Part A, but penalties may apply to other parts if you delay coverage.
If you or your spouse didn’t work enough hours and don’t qualify for Medicare premium-free Part A, you can still purchase it. You can sign up for Part A during your Initial Enrollment Period (IEP), a seven-month window that runs three months before the month you turn 65, your birthday month and three months after the month you turn 65. You will pay a monthly premium for coverage.
The amount you pay depends on how long you or your spouse worked and paid Medicare taxes. Every three months of work counts as one “work credit.” In 2026, you’ll pay a monthly premium of either $311 if you’ve accrued 30-39 work credits or $565 if you’ve accrued less than 30 work credits.
If you don’t sign up for Medicare Part A during your IEP, you’ll pay a late enrollment penalty. The penalty is 10 percent of the cost of your monthly premium. You’ll pay this extra cost every month for twice the number of years you were eligible for Medicare Part A but didn’t sign up.
For example, if you were eligible for Medicare Part A one year ago but didn’t sign up, you’ll pay the 10 percent premium penalty every month for two years.
You can delay enrolling in Part A without being penalized if you have creditable coverage. This is health insurance that’s as good as or better than what Medicare covers, such as through your or your spouse’s employer, for example.
Understanding the Medicare Part A penalty
Jennifer
Jennifer worked and paid Medicare taxes for 38 quarters. She wasn’t eligible for premium-free Medicare Part A and didn’t purchase Part A coverage when she was first eligible in 2024.
She wants to sign up in 2026 and will need to pay 10% of the cost of the monthly premium for twice the number of years she didn't enroll.
Jennifer's Medicare Part A penalty:
2026 monthly premium: $311 (based on 30-39 quarters of work)
Late enrollment penalty: +10% = $31.10/month
New monthly premium total cost: $342.10/month
Penalty duration: 2 Years (24 months)
Total penalty paid: $746.40 over 2 years
Medicare Part B late enrollment penalty
Like Medicare Part A, you can sign up for Medicare Part B during your IEP. However, if you decide not to enroll in Medicare Part B during this time — and you don’t qualify for a Special Enrollment Period — you’ll incur a late enrollment penalty. You may qualify for a Special Enrollment Period if you experience certain life events, such as a move or loss of other health coverage. Your monthly premium will increase by 10 percent for every 12-month period you were eligible for Medicare Part B but didn’t sign up. In most cases, you’ll need to pay this extra cost for as long as you have Part B.
Find out if you can still enroll in Medicare Part B without a penalty
Understanding the Medicare Part B penalty
Steven
Steven signed up for Part B coverage two years after his Initial Enrollment Period ended. Because he went without Medicare coverage for 24 months, he now has to pay a late enrollment penalty. Since there is a 10% late enrollment penalty for each 12-month period you go without Medicare coverage, Steven will pay 20% of the standard Part B premium. This is an added cost to his current Part B monthly premium.
Steven’s Medicare B penalty:
2026 monthly premium: $202.90
Late enrollment penalty: +20% = $40.58/month
New monthly premium total cost: $243.48/month
Penalty duration: For life of Part B coverage
Annual penalty paid: $486.96 over 1 year
Medicare Part D late enrollment penalty
You can sign up for a Medicare Part D prescription drug plan during your IEP when you’re also eligible to enroll in Medicare Part A and Part B. You can also enroll during the first three months after your Part A and Part B begin.
After that time, if you go without Part D or other creditable prescription drug coverage for 63 days or more in a row, you’ll pay a late enrollment penalty. Creditable prescription drug coverage pays, on average, as much as or more than a Part D plan.
Medicare calculates the Part D late enrollment penalty by multiplying 1 percent of the average monthly plan price by the number of months you were without coverage. The fee is added to your monthly premium for as long as you have a Part D plan.
You will not have to pay a late enrollment penalty if you’re eligible for a Special Enrollment Period and sign up then or are eligible for the Extra Help program.
Understanding the Medicare Part D penalty
Joe
Joe was without creditable prescription drug coverage from January 2024 to December 2024, or 12 months.
The penalty for Part D/prescription drug coverage is 1% of the average Part D premium multiplied by the number of months you are late enrolling.
Since Joe was 12 months late enrolling, his penalty is 12% of $38.99 (the average Part D premium in 2026).
Joe's Medicare D penalty:
2026 monthly premium: $38.99
Late enrollment penalty: +12% = $4.70 / month
New monthly premium total cost: $43.69 / month
Penalty duration: For life of Part D coverage
Annual penalty paid: $56.40 over 1 year
Medicare Advantage (Part C) enrollment periods
Though there are no late enrollment penalties for Medicare Advantage Part C plans, there are certain times when you can sign up or make changes to your coverage. These include:
- During your IEP
- During Annual Enrollment Period (October 15 to December 7)
- During Open Enrollment Period (January 1 to March 31)
- During a Special Enrollment Period
When preparing to enroll in Medicare, be sure to follow your Medicare plan enrollment schedule. Not only will this help ensure you have uninterrupted coverage, but it will also prevent you from paying penalty fees.
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