About the Medicare Part D Cost Calculator
This Medicare Part D cost calculator estimates what you will pay for prescription drugs in 2026 or 2027 under the redesigned Part D benefit. Enter the full monthly cost of your drugs (the plan’s negotiated price, before your share), your plan’s deductible, coinsurance and monthly premium. The calculator walks month by month through the deductible phase, the initial coverage phase and the catastrophic phase, and shows the month you hit the out-of-pocket cap.
It is built for people comparing Part D or Medicare Advantage drug plans during open enrollment, new enrollees budgeting their first year, and caregivers planning for an expensive specialty drug. Since 2025 the Inflation Reduction Act caps yearly out-of-pocket drug spending, so even very costly prescriptions now have a predictable ceiling.
For 2026 the standard benefit has a $615 maximum deductible, 25% coinsurance in the initial coverage phase and a $2,100 out-of-pocket threshold, after which you pay nothing more for covered drugs that year. For 2027 — the plan year you choose during the October 15 to December 7, 2026 open enrollment period — CMS has set the maximum deductible at $700 and the threshold at $2,400 (CY 2027 Rate Announcement). Real plans often use flat copays by drug tier instead of 25%; enter your average share to approximate them. Premiums do not count toward the cap, and drugs must be on your plan’s formulary.
With the default inputs, the total yearly cost (drugs + premiums) is $2,580.00. Change any value above to recalculate instantly.
How to use the medicare part d cost calculator
- 1Find the full monthly price of your drugs on Medicare Plan Finder or your plan’s drug price tool.
- 2Choose the plan year, then enter your plan’s deductible (up to $615 in 2026 or $700 in 2027) and monthly premium.
- 3Keep 25% coinsurance for the standard benefit, or enter your plan’s average share.
- 4Set the number of months you will be covered this year.
- 5Read your yearly total, the month you hit the cap and the month-by-month table.
Formula and method
The calculator follows the Part D phases month by month for the plan year you pick. In the deductible phase you pay the full negotiated price until you have paid the plan deductible (at most $615 in 2026 or $700 in 2027). In the initial coverage phase you pay your coinsurance share — 25% under the standard benefit — of each month’s drug cost. Once your out-of-pocket spending for covered drugs reaches the annual threshold — $2,100 in 2026, $2,400 in 2027 — you enter the catastrophic phase and pay nothing more for the rest of the calendar year.
Premiums are added separately because they never count toward the cap. The amount paid by others is the full drug cost minus your out-of-pocket share; it is split between your plan, drug manufacturers (through the manufacturer discount program) and Medicare.
- Cost
- Full negotiated monthly cost of your covered drugs
- Deductible
- Plan deductible, up to $615 in 2026 or $700 in 2027
- Coinsurance
- Your share after the deductible (25% standard)
- Cap
- Annual out-of-pocket threshold: $2,100 in 2026, $2,400 in 2027
Worked examples
$800 a month in drugs, standard benefit
In January you pay the $615 deductible plus 25% of the remaining $185 ($46.25), or $661.25. Each later month costs $200 (25% of $800), so you reach $2,061.25 by August and hit the $2,100 cap in September. Add $480 of premiums for $2,580 in total.
Modest prescriptions: $200 a month
A year of drugs costs $2,400. You pay the first $615 in full, then 25% of the remaining $1,785 ($446.25), for $1,061.25 out of pocket. With $480 of premiums the year costs $1,541.25 and the cap is never reached.
Specialty drug at $3,000 a month
January costs $615 + 25% × $2,385 = $1,211.25. February adds $750, bringing you to $1,961.25, and March takes you to the $2,100 cap. From then on covered drugs cost nothing, so the year totals $2,100 plus $480 of premiums.
2027 plan year: $800 a month with the $700 deductible
In January you pay the $700 deductible plus 25% of the remaining $100 ($25), or $725. Each later month costs $200, reaching $2,325 by September, so the $2,400 cap for 2027 is hit in October. With $480 of premiums the year costs $2,880.
Frequently asked questions
What is the Part D out-of-pocket cap for 2026?+
The annual out-of-pocket threshold is $2,100 in 2026, up from $2,000 in 2025. After your spending on covered drugs reaches that amount, you pay $0 for covered Part D drugs for the rest of the calendar year.
What is the maximum Part D deductible in 2026?+
Plans can charge a deductible of up to $615 in 2026 (it was $590 in 2025). Many plans charge less, and some have no deductible or exempt cheaper generic tiers from it.
What are the Part D limits for 2027?+
CMS set the 2027 standard Part D deductible at $700 and the annual out-of-pocket threshold at $2,400, up from $615 and $2,100 in 2026. Coinsurance in the initial coverage phase stays at 25% under the standard benefit.
Do premiums count toward the out-of-pocket cap?+
No. Only what you pay for covered drugs counts — deductible, copays and coinsurance. Monthly premiums and any IRMAA surcharge are extra and continue all year even after you reach the cap.
Is the coverage gap (donut hole) still around?+
No. The coverage gap was eliminated in 2025 when the benefit was redesigned into three phases: deductible, initial coverage and catastrophic, with the annual cap replacing the old gap rules.
What is the Medicare Prescription Payment Plan?+
It is an optional program that lets you pay your Part D out-of-pocket costs in monthly installments over the calendar year rather than all at the pharmacy. It does not reduce what you owe but smooths large early-year bills.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.