5 Medicare Penalties You Did Not Know Existed (and How to Avoid Them)

Medicare penalties are one of the most misunderstood aspects of the entire system. Most people have no idea these penalties exist until they receive a bill that is higher than expected, and by then it may be too late. Some of these penalties are permanent, meaning they follow you for as long as you have Medicare coverage.

I have seen firsthand how these penalties affect real people. Here are 5 Medicare penalties that catch people off guard, along with exactly what you can do to avoid each one.

1. The Part B late enrollment penalty

If you do not sign up for Medicare Part B when you are first eligible and you do not have qualifying employer coverage, you will pay a penalty of 10% of the standard Part B premium for every full 12-month period you could have had Part B but did not. This penalty is added to your monthly premium for as long as you have Part B.

For example, if you delayed Part B enrollment for two years without qualifying coverage, you would pay a 20% surcharge on your Part B premium every single month going forward. In 2026, with the standard Part B premium, that adds up quickly over time.

How to avoid it: Enroll in Part B during your Initial Enrollment Period (the 7-month window around your 65th birthday) unless you have creditable employer coverage. If you are still working and covered by your employer's group health plan, you may be able to delay without penalty, but you must enroll within 8 months of leaving that coverage.

2. The Part D late enrollment penalty

If you go 63 consecutive days or more without creditable prescription drug coverage after your Initial Enrollment Period ends, you will owe a Part D late enrollment penalty. The penalty is calculated as 1% of the national base beneficiary premium multiplied by the number of full months you went without coverage.

This penalty is added to your Part D premium every month for as long as you have a Part D plan. For someone who went without coverage for 24 months, that is an additional surcharge of roughly $8 to $10 per month, permanently.

How to avoid it: Enroll in a Part D plan or a Medicare Advantage plan with drug coverage during your Initial Enrollment Period. If you have creditable drug coverage through an employer or union, keep documentation proving it was creditable. You will need this if you enroll in Part D later.

3. The Part A late enrollment penalty

Most people get Part A premium-free because they (or their spouse) paid Medicare taxes for at least 40 quarters (10 years). But if you do not qualify for premium-free Part A and you do not enroll when first eligible, you may pay a penalty of 10% of the Part A premium. This penalty applies for twice the number of years you could have been enrolled but were not.

How to avoid it: If you are not sure whether you qualify for premium-free Part A, check with Social Security. Most people are automatically enrolled, but if you are not and you need to buy Part A, do not delay.

4. IRMAA: The income-related premium surcharge

This is not technically a "penalty," but it catches many people off guard. If your modified adjusted gross income exceeded certain thresholds two years ago, you will pay a higher premium for both Part B and Part D. This is called the Income-Related Monthly Adjustment Amount (IRMAA).

The lookback period is two years. So in 2026, Medicare looks at your 2024 tax return. If you sold a home, withdrew a large amount from a retirement account, or had any other income spike in 2024, you could face significantly higher premiums in 2026.

How to avoid or reduce it: If you have experienced a qualifying life-changing event (retirement, reduction in work hours, death of a spouse, divorce, loss of income-producing property), you can file Form SSA-44 with Social Security to request a new initial determination based on your current income rather than the two-year-old return.

5. The Medicare Advantage disenrollment gap

If you disenroll from a Medicare Advantage plan and return to Original Medicare outside of specific enrollment periods, you could end up with a gap in drug coverage. This gap can trigger the Part D late enrollment penalty described above, and it may also leave you without supplemental coverage at a time when Medigap underwriting rules could work against you.

How to avoid it: Before making any changes to your Medicare Advantage plan, consult with a dedicated agent who can map out the implications. Switching from Medicare Advantage back to Original Medicare requires careful timing to avoid coverage gaps and potential penalties.

Every one of these penalties is avoidable with the right guidance and timing. That is why working with a dedicated agent, rather than going it alone, makes such a difference.

What to do if you already have a penalty

If you believe you are paying a penalty in error (for example, because you had creditable coverage that was not properly reported), you may be able to appeal. The appeals process varies depending on the type of penalty, but a dedicated agent can help you determine whether you have grounds to challenge it and guide you through the paperwork.