If your first Medicare bill is higher than expected, it could be due to the number of months the bill covers, late enrollment penalties, or because you earn above a certain amount and must pay a surcharge.

You may not often receive high cost Medicare premium bills, as the federal government covers many of the plan costs.

But the costs when you first enroll with Medicare could be higher than expected for a number of reasons.

Original Medicare comprises Part A, which covers inpatient care, and Part B, which covers outpatient medical services.

Depending on your working history, you may be eligible for premium-free Part A services, so Medicare would not need to send a bill for this Part. People who do not qualify for premium-free Part A will receive a bill every month.

Part B premiums are typically deducted from your Social Security or Railroad Retirement Board benefits. Those who do not receive these benefits will receive a Part B bill every 3 months.

You may find your first Medicare bill to be higher than expected due to the following reasons.

If you pay for Part B only, you’ll receive a bill every 3 months. And because of this, it will include 3 months’ worth of premiums.

The bill may also include a further 3 months, as you pay for them in advance.

First bill example

  • You enroll with Medicare in February, and your coverage begins on February 1st.
  • Medicare bills its premiums quarterly, so the first bill would be dated the end of March.
  • Premiums would cover February 1 through April 30. (February, March, and April)
  • It would also include the following 3 months of May, June, and July.
  • Medicare has billed for a total of 6 months.

After this, you’d only receive a bill for 3 months’ worth of premiums, and you can check your billing dates to ensure they’re correct.

If your income is higher than a specific amount, you may have to pay an income-related monthly adjustment amount (IRMAA). Medicare adds this additional surcharge to the base Part B and Part D premiums.

An IRMAA is based on your reported income from your tax return 2 years prior. For example, your 2025 IRMAA would be decided by your reported income from 2023.

You’ll receive a notification from Social Security if you have to pay an IRMAA surcharge.

»Learn more:All about IRMAA

You typically become eligible for Medicare when you turn age 65, and your initial enrollment period (IEP) runs for 7 months. The IEP begins 3 months before you turn age 65, continues throughout your birth month, and ends 3 months later.

If you do not enroll during your IEP, or one of the other Medicare enrollment periods, and do not have alternative creditable coverage, you may have to pay a late enrollment penalty.

The Part A late enrollment penalty

If you pay a Part A premium but did not enroll during your IEP, you may have to pay a 10% penalty, which is added to your premium for twice the number of years you delayed enrollment.

For example, if you waited 1 year to enroll and did not have alternative creditable coverage, you’d pay 10% more for 2 years.

The Part B late enrollment penalty

The Part B late enrollment penalty is added to your Part B premium and will apply for as long as you have Medicare.

The penalty is an extra 10% of the Part B premium for each year you did not enroll when you could have.

For example, if you do not enroll for 2 years, you’ll pay 20% of the Part B premium in the year you enroll, which in 2025 would be 20% of $185.

The Part D late enrollment penalty

Part D prescription drug plans cover take-home prescription medications. Private insurers administer these plans. And while the premium costs can vary by insurer, the penalty will apply to the national base beneficiary premium.

You’ll pay a 1% penalty for each month you were eligible for Part D prescription drug coverage but did not enroll, and the following apply:

  • You did not enroll in a Part D plan when you were first eligible.
  • You went without creditable coverage for 63 days or more.

The Part D penalty is added to your monthly bill and will remain in place for as long as you have the plan.

It’s important to enroll in Medicare when you’re first eligible. And ensure you have suitable alternative coverage to avoid late enrollment penalties.

If your Medicare premiums are not automatically deducted from your Social Security checks, you can pay your premiums:

  • online, though your Medicare account
  • through Medicare Easy Pay
  • through your bank account
  • through the mail, by completing the coupon that came with your bill and returning it to:
    • Medicare Premium Collection Center
      PO Box 790355
      St. Louis, MO 63179-0355

Your first Medicare bill may be higher than expected for a number of reasons.

Depending on when you enrolled, the bill may cover a longer period, there could be late enrollment penalties, or there may be an income-related surcharge.

If you have questions about Medicare billing, you can contact Medicare at 800-633-4227 (TTY: 877-486-2048) or via the Medicare website.