Medicare Part D costs most people between roughly $26 and $58 per month in premiums alone, depending on the plan and where you live. But premiums are only one piece of the total cost. Your actual spending depends on a combination of your monthly premium, an annual deductible, copays at the pharmacy counter, and whether your income triggers a surcharge.
Monthly Premiums
There’s no single price for Part D. Each insurance company sets its own premium, and prices vary widely by state. In 2024, the cheapest state average for standalone Part D plans was $26.43 per month in South Dakota, while New York had the highest at $57.58, according to KFF enrollment-weighted data. The plan you choose within your state matters just as much as geography: in any given area you’ll find plans ranging from budget options with narrow drug lists to pricier plans that cover more medications with lower copays.
The national base beneficiary premium, a benchmark figure set by Medicare each year, is $38.99 for 2026. This number doesn’t represent what you’ll actually pay. It’s used as a reference point for calculating penalties and surcharges, but it gives a rough sense of where average costs land.
The Annual Deductible
Before your plan starts sharing costs with you, most Part D plans charge a deductible. For 2025, the maximum allowable deductible is $590. For 2026, it rises to $615. Some plans set their deductible lower than the maximum, and a handful of plans have no deductible at all, though those tend to carry higher monthly premiums to compensate. During the deductible phase, you pay full price for your prescriptions.
What You Pay at the Pharmacy
Once you’ve met your deductible, you enter the initial coverage stage. Here, you typically pay 25% of the cost of both generic and brand-name drugs, with your plan covering the other 75%. What this actually costs you per prescription depends on which “tier” your drug falls into. Plans organize their covered drugs into tiers:
- Tier 1 (lowest cost): most generic drugs
- Tier 2 (medium cost): preferred brand-name drugs
- Tier 3 (higher cost): non-preferred brand-name drugs
- Specialty tier (highest cost): very expensive drugs, often for complex conditions
A Tier 1 generic might cost you a few dollars per fill, while a specialty-tier drug could run several hundred. The exact copay or coinsurance percentage varies from plan to plan, which is why comparing formularies (the list of drugs each plan covers) matters so much when choosing a Part D plan.
The $2,000 Out-of-Pocket Cap
Starting in 2025, a hard annual cap on out-of-pocket drug spending took effect thanks to the Inflation Reduction Act. For 2025, that cap is $2,000. For 2026, it rises slightly to $2,100. Once your total out-of-pocket spending on covered Part D drugs hits that threshold, you enter catastrophic coverage and pay nothing for the rest of the calendar year. This is a major change from previous years, when there was no true spending cap and people taking expensive medications could face thousands of dollars in ongoing costs.
This means the absolute maximum you’d spend on covered drugs in 2026, not counting premiums, is $2,100. For someone who takes only a couple of inexpensive generics, total drug costs for the year might be a few hundred dollars. For someone on costly specialty medications, the cap prevents bills from spiraling beyond that $2,100 ceiling.
Income-Related Surcharges
Higher earners pay more for Part D through a surcharge called IRMAA (Income-Related Monthly Adjustment Amount). Medicare looks at your tax return from two years prior to determine whether you owe extra. For 2026, the surcharges for single filers break down like this:
- Income $109,001 to $137,000: $14.50 per month added to your plan premium
- Income $137,001 to $171,000: $37.50 per month
- Income $171,001 to $205,000: $60.40 per month
- Income $205,001 to $499,999: $83.30 per month
- Income $500,000 or more: $91.00 per month
For married couples filing jointly, the thresholds are roughly doubled. At the top bracket, you’d pay an extra $91 per month on top of whatever your plan charges, adding over $1,000 per year to your Part D costs. If your income has dropped significantly since the tax year Medicare is using (due to retirement, for example), you can appeal the surcharge through Social Security.
Late Enrollment Penalties
If you don’t sign up for Part D when you’re first eligible and go 63 or more consecutive days without creditable drug coverage (coverage that’s at least as good as a standard Part D plan), you’ll owe a permanent penalty when you do eventually enroll. The penalty is 1% of the national base beneficiary premium for every month you went without coverage. That’s 12% per year of delay.
Here’s how it adds up: say you waited 14 months past your eligibility window. In 2026, 14% of the $38.99 base premium rounds to $5.50 per month. That $5.50 gets tacked onto your monthly premium for as long as you have Part D coverage. The penalty recalculates each year as the base premium changes, so it can grow over time. Even if you don’t take any medications right now, this permanent surcharge is why most people enroll on time.
Help for Lower Incomes
Medicare’s Extra Help program (also called the Low-Income Subsidy) covers most or all Part D costs for people with limited income and savings. For 2026, individuals earning up to $23,940 per year with resources under $18,090 can qualify. For married couples, the limits are $32,460 in income and $36,100 in resources. “Resources” includes savings, investments, and real estate beyond your primary home, but not your house or car.
If you qualify, Extra Help can eliminate your premium, reduce your deductible to zero, and drop your copays to a few dollars per prescription. Even partial qualification significantly lowers costs. You can apply through Social Security’s website or your local Social Security office.
Putting the Total Cost Together
Your total annual Part D cost is premiums plus deductible plus copays at the pharmacy. For someone on a few generic medications with an average-premium plan, a realistic annual total might look something like $35 per month in premiums ($420/year), a $590 deductible, and modest copays through the year, landing somewhere around $700 to $1,200 total. For someone taking expensive brand-name or specialty drugs, costs can climb quickly but will now cap at roughly $2,100 in drug costs plus whatever your annual premiums total.
The single most effective way to lower your Part D costs is to compare plans during open enrollment each fall (October 15 through December 7). Plans change their formularies, copay structures, and premiums every year, so the cheapest plan for your specific medications may be different from the one you’re currently on. Medicare’s Plan Finder tool at medicare.gov lets you enter your exact prescriptions and pharmacy to see the estimated total annual cost for every plan available in your area.