Late enrollment in Medicare or a higher income can lead to higher premiums. However, everyone has the right to appeal their premium determination. Understanding how these premiums work can help you assess their accuracy and decide if you should appeal. Download a detailed handout from the Medicare Rights Center here.

Income-Related Monthly Adjustment Amount (IRMAA)

The Medicare Income-Related Monthly Adjustment Amount, often shortened to IRMAA, is an amount you may owe in addition to your Part B and Part D premium if your income is above a certain level. Federal law sets income brackets that determine your—or you and your spouse’s—IRMAA each year.

Find the chart of monthly premiums for Part B and Part D based on your annual income here.

You can ask for a new IRMAA determination. If the Social Security Administration determines that you owe an IRMAA, they will mail you a notice called an initial determination. This notice should include information on how to request a new initial determination. A new initial determination is a revised decision that Social Security makes regarding your IRMAA. You can request that Social Security revisit its decision if you have experienced a life-changing event that caused an income decrease, or if you think the income information Social Security used to determine your IRMAA was incorrect.

Part B Late Enrollment Penalty

For each 12-month period you delay enrollment in Medicare Part B, you will owe a 10% Part B late enrollment penalty (LEP)—generally every month for as long as you have Medicare. Everyone has a right to file an appeal with the Social Security Administration (SSA) regarding their LEP. To appeal, follow the directions on the letter informing you about the penalty. Unfortunately, being unaware of the requirement to enroll in Part B is unlikely to be a successful argument for an appeal.

How to calculate the Part B LEP:

Let’s say you delayed enrolling in Medicare Part B for seven years and you owe a premium penalty. Your monthly premium would be 70% higher for as long as you have Medicare (7 years x 10%). Since the base Part B premium in 2025 is $185, your monthly premium with the penalty will be $314.50 ($185 x 1.7).

Part D Late Enrollment Penalty

For each month you delay enrollment in Part D, you will owe a 1% Part D LEP (generally every month for as long as you have Part D). The Part D penalty is always calculated using that year’s national base beneficiary premium. Your penalty will not decrease if you enroll in a Part D plan with a lower premium.

Everyone has the right to file an appeal with C2C Innovative Solutions regarding their LEP determination. C2C Solutions is the company contracted by Medicare to handle these appeals. You can appeal the penalty (if you think you were continuously covered) or its amount (if you think it was calculated incorrectly). You should complete the appeal form you received from your plan, attach any evidence you have, and mail everything to C2C Innovative Solutions.

How to calculate the Part D LEP:

Let’s say you delayed enrollment in Part D for seven months (and you didn’t have other creditable drug coverage, which allows you to delay enrollment). Your monthly premium would be 7% higher for as long as you have Part D (7 months x 1%). The national base beneficiary premium in 2025 is $36.78 a month. Your monthly premium penalty would therefore be $2.57 ($36.78 x 0.07 = $2.57) per month, which you would pay in addition to your plan’s premium.

Identify billing errors

Health care providers and their billing departments sometimes make billing errors or honest mistakes. If you think your doctor or their billing department made an error or mistake, contact them directly to resolve the issue. They should correct these errors if you tell them.

You can spot these errors by keeping an appointment calendar or using a My Health Care Tracker to keep track of your medical appointments and services. You can call your local Senior Medicare Patrol (SMP) for a My Health Care Tracker if you don’t already use one. The tracker can help you compare your appointments, services, and notes to your Medicare statements.

If something does not seem right on your Medicare statement, remember to first call your provider. Here are just a couple examples of potential errors:

• Your provider billed Medicare for an office visit on a day when you did not see them.
• Your provider billed you for a service that was different than what you received.

If your provider does not resolve the issue, or if you notice a pattern of errors, contact your local Senior Medicare Patrol (SMP). In Southwest Florida, call 866-413-5337. They can assist to try to resolve the error. Your SMP can also help you identify Medicare potential fraud, or abuse, and can help you report it to CMS and the correct authorities.

SHINE counselors can also provide you with individual Medicare counseling to support you in your specific situation. Call us at 866-413-5337 or email shineinfo@aaaswfl.org.