As we age, staying active and independent means being able to afford the prescription medications we need to manage our health, including chronic conditions. While Medicare Parts A and B cover doctor’s visits and hospital stays, Medicare Part D (prescription drug coverage) helps older adults pay for the cost of prescription drugs.

Part D covers outpatient prescription drugs through a standalone plan that works with original Medicare (Parts A and B), or as part of the benefits provided by a Medicare Advantage (Part C) plan. 

There are a few key things you need to know about Medicare Part D to get the most out of your plan. Below, we share five important facts about Part D costs and coverage to help you make a confident, informed enrollment decision

1. Medicare Part D is not free  

While Part D provides important benefits, it’s not free for most people. Below are some of the out-of-pocket expenses you can expect to pay in 2025.

Part D cost sharing

Most people who are enrolled in a Part D plan (and not eligible for the Part D Low-Income Subsidy/LIS or "Extra Help") are responsible for certain expenses. These may include:

• A monthly Part D plan premium (average estimated premium in 2024 is $46.50)
• An annual deductible (maximum $590 in 2025)
• A copayment or coinsurance during the initial coverage period

To better understand how the Part D benefit works and how much you may have to spend, see our 2025 Part D Standard Plan Cost-Sharing Chart.

Note: Some people with higher incomes will pay more for their Part D premiums. This is called IRMAA, or income-related monthly adjustment amount. Learn more about IRMAA.

2. The Inflation Reduction Act has helped lower Medicare Part D costs—and there’s more to come

The Inflation Reduction Act of 2022 introduced many important changes for Part D beneficiaries. In 2024, eligibility for the full Medicare Part D Low-Income Subsidy (LIS, or "Extra Help") was expanded to beneficiaries with incomes up to 150% of hte federal poverty level (FPL). LIS lowers premiums and out-of-pocket costs for prescription drugs.

Now, beneficiaries no longer pay a premium if they're enrolled in a benchmark plan. They also have no deductible and fixed, lower copayments (up to $4.90 for generic and $12.15 for brand-name drugs in 2025).

In addition, the Limited Income Newly Eligible Transition (LINET) program became permanent in 2024. LINET provides immediate but temporary Part D prescription drug coverage for low-income Medicare beneficiaries who qualify for LIS/Extra Help but have no drug coverage. This benefit is available for up to two months until a person enrolls in a Medicare drug plan.

People who receive both Medicare and Medicaid benefits ("dual eligibles") are automatically enrolled in LINET. If you're not dual-eligible but think you may qualify for LINET, ask your pharmacist.

Other Part D changes that began in 2024 thanks to the Inflation Reduction Act include:

• Limit on insulin copays to $35
• Elimination of 5% coinsurance for Part D catastrophic coverage
• Drug companies required to pay rebates if drug prices rise faster than Inflation
• No cost-sharing for adult vaccines covered under Part D

The following changes will take effect in 2025:

• $2,000 maximum annual out-of-pocket cap on Medicare Part D prescription drug costs
• Elimination of the coverage gap to simplify the Part D benefit

3. You can spread your out-of-pocket drug costs across the calendar year

Do you take a costly medication and can't afford a large copayment at the pharmacy? As of 2025, Part D beneficiaries have the option to spread their drug costs out in a series of monthly payments over the calendar year (January to December). This new, voluntary Medicare Prescription Payment Plan (called the M3P option) will be offered by all Part D plans. It's more useful earlier in the year, before you reach the $2,000 cap on out-of-pocket costs.

4. The Part D coverage gap is eliminated in 2025

Through the end of 2024, if you exceed the spending threshold in the initial coverage period of Part D, you enter the Part D coverage gap or "donut hole." In this gap, you must pay a higher percentage of drug costs until you reach the out-of-pocket spending limit.

However, as of January 1, 2025, the coverage gap is eliminated, and annual out-of-pocket Part D costs are capped at $2,000. This means if you take high-cost medications covered by Part D, you could see major savings. After meeting the out-of-pocket limit, you pay $0 for covered drugs for the rest of the year.

5. You can be penalized for enrolling late in Part D

If you delay enrollment in Medicare Part D, and you do not have other prescription drug coverage, you’ll likely have to pay high costs out of pocket. In addition, if you enroll in Part D outside your eligibility window (which is your Initial Enrollment Period), you could face a late enrollment penalty. This penalty was created to help ensure more older adults have timely access to prescription drug coverage.

How does the Part D late enrollment penalty work? It’s a monthly add-on premium calculated as 1% of the current national base beneficiary premium ($36.78 in 2025) multiplied by the number of uncovered months, rounded to the nearest 10 cents. This amount is added to the Part D monthly premium. The penalty is recalculated yearly based on that year's base premium amount.

In most cases, the Part D penalty stays in force for as long as you have drug coverage through Medicare—even if you switch Part D plans. You can avoid it by enrolling in a Part D plan within your eligibility window.

Where can I get help choosing a Medicare plan?

The online Medicare plan finder can help you compare Part D plans and settle on the one that's best for you. Want personal, one-on-one assistance? Get in touch with your local State Health Insurance Assistance Program (SHIP). A certified SHIP counselor can help you:

• Learn the basics of Medicare and explore your coverage options. 
• Understand Medicare's out-of-pocket costs (and find programs to help you pay for them).
• Ensure your rights are protected under Medicare.

Find your local SHIP office here or call 1-877-839-2675 to connect with a Medicare counselor.  This free, unbiased service is available to all Medicare-eligible adults and their families and caregivers.