Medicare Part D is not free for most people. You’ll typically pay a monthly premium, an annual deductible, and copays or coinsurance each time you fill a prescription. However, the actual cost varies widely depending on which plan you choose, how much income you earn, and whether you qualify for financial assistance. Some people pay nothing at all for Part D coverage, while others pay well over $100 per month.
What Part D Typically Costs in 2025
Every Part D plan sets its own monthly premium, but the national base beneficiary premium for 2025 is $36.78. That number is a benchmark, not a price tag. Your actual premium could be lower or higher depending on the plan you pick. Some standalone Part D plans charge less than $10 per month, while others charge significantly more based on the drugs they cover and the pharmacy networks they use.
Beyond the monthly premium, the maximum annual deductible a Part D plan can charge in 2025 is $590. You pay 100% of your prescription costs until you hit that amount. Many plans set their deductible lower than the maximum, and some waive it entirely for certain categories of drugs like generics. After meeting the deductible, you’ll pay copays or coinsurance for each prescription until you reach the annual out-of-pocket cap.
The $2,000 Out-of-Pocket Cap
Starting in 2025, no Part D enrollee will spend more than $2,000 out of pocket on covered prescription drugs in a calendar year. This cap, created by the Inflation Reduction Act, replaced the old “catastrophic coverage” phase where enrollees still owed 5% of drug costs with no upper limit. Once your copays and coinsurance add up to $2,000, your plan covers everything for the rest of the year. The cap will be adjusted for inflation annually.
This is a major change for people who take expensive medications. Previously, someone on a specialty drug for cancer or autoimmune disease could face thousands of dollars in annual out-of-pocket costs even after reaching catastrophic coverage. That’s no longer possible.
$0 Premium Plans Through Medicare Advantage
Some Medicare Advantage plans bundle drug coverage with hospital and medical benefits at a $0 monthly premium. These plans are widely available, and they can make Part D feel “free” in terms of the premium. But $0 premium plans still come with out-of-pocket costs when you actually use them: copays for prescriptions, deductibles, and coinsurance for medical services.
The trade-offs matter. Zero-premium plans often have narrower pharmacy and provider networks, meaning you may need to use specific pharmacies or get prior authorization before your plan covers certain medications. They also set their own formularies, so a drug covered under one plan may not be covered under another. Before choosing a plan based on premium alone, check whether your specific medications are on the plan’s drug list and what the copay will be at your preferred pharmacy.
Who Actually Pays Nothing
Medicare’s Extra Help program (also called the Low-Income Subsidy) can eliminate or dramatically reduce all Part D costs, including premiums, deductibles, and prescription copays. To qualify in 2025, your annual income must be below $23,475 if you’re single or $31,725 if you’re a married couple living together. Your countable assets (savings, investments, and real estate other than your home) must be under $18,090 for an individual or $36,100 for a couple.
If you qualify for full Extra Help, Part D is essentially free. You pay little to nothing for monthly premiums, skip the deductible, and pay only small copays for prescriptions, often just a few dollars. People who are enrolled in both Medicare and Medicaid automatically qualify. You can apply through the Social Security Administration.
High Earners Pay More
If your income is above a certain threshold, you’ll pay a surcharge on top of your regular Part D premium. Medicare calls this the Income-Related Monthly Adjustment Amount, or IRMAA. It’s based on your tax return from two years prior.
- $106,000 or less (single) / $212,000 or less (joint): No surcharge
- $106,001 to $133,000 (single) / $212,001 to $266,000 (joint): $13.70 per month
- $133,001 to $167,000 (single) / $266,001 to $334,000 (joint): $35.30 per month
- $167,001 to $200,000 (single) / $334,001 to $400,000 (joint): $57.00 per month
- $200,001 to $499,999 (single) / $400,001 to $749,999 (joint): $78.60 per month
- $500,000 or more (single) / $750,000 or more (joint): $85.80 per month
These surcharges are added to whatever your plan’s regular premium is. So if your plan costs $40 per month and your IRMAA is $35.30, your total monthly premium would be $75.30. Most Medicare beneficiaries fall in the first bracket and pay no surcharge at all.
The Cost of Not Signing Up
If you don’t enroll in Part D when you’re first eligible and you go 63 or more consecutive days without comparable drug coverage, Medicare charges a late enrollment penalty. The penalty is 1% of the national base beneficiary premium for every month you went without coverage. It’s added to your monthly premium permanently.
Here’s how that adds up. Say you went 14 months without Part D or equivalent coverage. Using the 2026 base premium of $38.99, your penalty would be 14% of that amount, or about $5.50 per month, every month, for as long as you have Part D. Over 10 years, that’s roughly $660 in extra costs. The penalty recalculates each year as the base premium changes, so it grows over time. Even if you don’t take any prescriptions now, enrolling in a low-cost plan when you’re first eligible avoids this permanent surcharge.