Medicare Part D has five separate price tags, and most people only shop for one of them. There is the monthly premium, the annual deductible, the coinsurance you pay at the counter, an income surcharge that hits about 8% of enrollees, and a ceiling on the whole thing that did not exist three years ago.
Every figure below was pulled on September 6, 2026 from CMS, Medicare.gov and KFF. Where CMS has already announced the 2027 number, it is printed next to the 2026 number and labeled. Open enrollment for plan year 2027 runs October 15 to December 7, 2026, so both vintages matter right now.
What Medicare Part D Costs in 2026
| Cost component | 2026 amount | Notes |
|---|---|---|
| National base beneficiary premium | $38.99 | CMS, July 28, 2025 release. A formula input, not a bill. 2027: $41.33 |
| Average stand-alone plan premium | $36/month | KFF analysis of CMS data, June 2026. Down from $39 in 2025 |
| Range across the 10 national stand-alone plans | $0 to $116/month | KFF, October 2025. SilverScript Choice alone spans $14.70 to $116 by state |
| Average Part D premium inside a Medicare Advantage plan | $8/month | KFF, June 2026. 79% of MA-PD enrollees without Extra Help pay $0 for drug coverage |
| Maximum allowable annual deductible | $615 | CMS Final CY 2026 Redesign Program Instructions. 2027: $700 |
| Average deductible actually charged (stand-alone plans) | $544 | KFF, June 2026. 78% of enrollees face the full $615 |
| Coinsurance after the deductible | 25% | Defined standard benefit, initial coverage phase |
| Annual out-of-pocket cap | $2,100 | CMS. Hard ceiling. 2027: $2,400 |
| Insulin, per month supply | $35 max | Medicare.gov. No deductible applies |
| ACIP-recommended adult vaccines | $0 | Shingles, Tdap and others, no deductible |
| Part D income surcharge (IRMAA) | $0 to $91.00/month | CMS, November 14, 2025. Starts above $109,000 individual income |
The Premium You Pay Is Not the Base Premium
The $38.99 figure gets quoted constantly as “the 2026 Part D premium.” It is not. CMS calls it the national base beneficiary premium, and its job is to be a formula input: it sets the low-income subsidy benchmark and it is the multiplier in the late enrollment penalty. Nobody is billed $38.99 because that is the number.
What people actually pay is set plan by plan. KFF’s June 11, 2026 analysis of CMS enrollment data puts the weighted average stand-alone plan premium at $36 a month in 2026, down 7% from $39 in 2025. Inside a Medicare Advantage drug plan the average drug-coverage premium is $8 a month, because Advantage plans can spend federal rebate dollars buying it down. That gap is one of the real dividing lines in Medicare Advantage versus Original Medicare.
The spread underneath those averages is enormous. In KFF’s October 2025 read of the 2026 landscape, one national plan, SilverScript Choice, ranged from $14.70 to $116 a month depending on the state. Wellcare Classic ranged from $0 to $45.70. About 28% of stand-alone plan enrollees pay no premium at all, while 20% pay $100 a month or more. Among everyone who pays something, the average is $57.
For 2027, CMS announced a base beneficiary premium of $41.33 on July 28, 2026, a 6% increase that is the statutory maximum. CMS also announced in the same memo that it is ending the Part D Premium Stabilization Demonstration after 2026, which had been shaving $10 off the base premium and capping any single plan’s year-over-year increase at $50. Actual 2027 plan premiums land with the CMS landscape files in late September.
The Deductible and the 25% Coinsurance
No Part D plan may charge a deductible above $615 in 2026. That ceiling rises to $700 in 2027 under Table V-6 of the CY 2027 Rate Announcement.
Plans are allowed to charge less. Increasingly they do not. KFF found that 78% of stand-alone plan enrollees face the full $615 in 2026 and only 4% have no drug deductible at all, down from 15% in 2025. The weighted average stand-alone deductible is $544.
After the deductible you are in the initial coverage phase, paying 25% coinsurance on covered drugs until your out-of-pocket total hits the cap. Which drugs and at what tier is entirely a function of your plan’s formulary, which is why two people on the same medication in the same zip code can pay wildly different amounts.
The $2,100 Cap
This is the single most important number in Part D and the one most people do not know exists. Once your out-of-pocket spending on covered Part D drugs reaches $2,100 in 2026, you pay $0 for covered drugs for the rest of the calendar year. CMS set the 2027 threshold at $2,400.
The cap replaced the old coverage gap, which is gone. If you are looking for the Medicare donut hole, it was eliminated effective January 1, 2025.
Two carve-outs sit outside the normal math. Insulin is capped at $35 for a one-month supply of each covered product, with no deductible, so a three-month supply cannot exceed $105. Adult vaccines recommended by the CDC’s advisory committee, including shingles and Tdap, cost $0 with no deductible. If insulin is your main drug expense, compare that $35 against retail insulin pricing before assuming a plan is the cheaper route.
The Part D IRMAA Surcharge
If your modified adjusted gross income from two years back crosses a threshold, Social Security adds an income-related monthly adjustment amount on top of whatever your plan charges. It is billed separately from the plan premium, usually deducted from your Social Security check. CMS published these 2026 brackets on November 14, 2025.
| 2026 individual MAGI | Joint MAGI | Added per month |
|---|---|---|
| $109,000 or less | $218,000 or less | $0.00 |
| Over $109,000 to $137,000 | Over $218,000 to $274,000 | $14.50 |
| Over $137,000 to $171,000 | Over $274,000 to $342,000 | $37.50 |
| Over $171,000 to $205,000 | Over $342,000 to $410,000 | $60.40 |
| Over $205,000 to under $500,000 | Over $410,000 to under $750,000 | $83.30 |
| $500,000 or more | $750,000 or more | $91.00 |
CMS says roughly 8% of people with Part D pay one of these. The 2027 brackets are not out yet: CMS publishes them each November alongside the Part B premium fact sheet, and as of September 6, 2026 no 2027 figure has been released. If your income dropped because of retirement, divorce or a spouse’s death, the surcharge can be reversed through an IRMAA appeal.
What a Typical Year Actually Costs
Take the average stand-alone plan at $36 a month. That is $432 a year in premiums before a single prescription is filled. Add the deductible and coinsurance and a moderate drug user might land somewhere between $700 and $1,500 for the year.
The useful thing about 2026 is that the ceiling is now knowable. Premiums plus $2,100 is the absolute worst case for covered drugs. At the $36 average premium that is $2,532 for the year, no matter how expensive your medications are. Someone on a specialty drug who would have spent $5,000 or more in 2023 now stops at that line.
Why the Cheapest Premium Is Usually Not the Cheapest Year
Plans trade premium against cost sharing, and the trade is stark. KFF’s 2026 data shows the 4% of stand-alone enrollees in a zero-deductible plan pay an average premium of $127 a month, while the 78% in a plan charging the full $615 deductible pay an average of $22 a month.
Run the arithmetic on those two. The zero-deductible plan costs $1,524 a year in premiums. The full-deductible plan costs $264 a year in premiums plus up to $615 in deductible, or $879 if you exhaust it. The low-premium plan wins by roughly $645 even in the worst case, and by far more if you barely use it. That is not a universal rule, it is a demonstration that premium alone decides nothing.
What actually decides it is whether your specific drugs are on the plan’s formulary, at what tier, and at which pharmacies. That comparison is the whole job of choosing a Part D plan, and Medicare’s Plan Finder will do it if you enter your actual prescription list.
The Late Enrollment Penalty
If you go 63 days or more without creditable drug coverage after your initial enrollment period ends, Medicare adds 1% of the national base beneficiary premium for every uncovered month, permanently. In 2026 that is 1% of $38.99, about $0.40 a month per uncovered month, rounded to the nearest 10 cents. Twelve uncovered months costs roughly $4.70 a month for life, and the dollar amount is recalculated every January as the base premium moves. Full mechanics are in the Part D late enrollment penalty guide.
What Lowers the Bill
Two federal programs change the arithmetic rather than the shopping.
Extra Help, the Part D low-income subsidy, wipes out the deductible, covers the premium up to your region’s benchmark, and replaces coinsurance with flat copays of $5.10 generic and $12.65 brand in 2026. If you qualify, nothing else on this page applies to you in the same way. Medicare Savings Programs are the adjacent door and enrolling in one gets you Extra Help automatically.
The Medicare Prescription Payment Plan spreads that same $2,100 across the remaining months of the year at zero interest. It does not reduce the total by a dollar. It exists for the person facing a $600 January.
Outside Medicare entirely, prescription assistance programs and cash prices at Cost Plus Drugs sometimes beat a plan copay on generics. The catch is that cash spending outside your plan does not count toward the $2,100 cap, so it is a good move on cheap generics and usually a bad one on the expensive drug that would otherwise carry you to the ceiling.
Bottom Line
Budget for four numbers in 2026: a premium that averages $36 but ranges from $0 to $116 across the national plans, a deductible up to $615, 25% coinsurance, and a hard stop at $2,100. Add an IRMAA surcharge of $14.50 to $91.00 a month if you are above $109,000 in income. For 2027, the deductible ceiling is $700 and the cap is $2,400, both already final. Everything else about 2027 lands in late September and November. If you are new to all of this, start with how the Medicare parts fit together and the Part D overview.