Medicare Part D Premium
Medicare Part D — the outpatient prescription drug benefit authorized under 42 U.S.C. §§ 1395w-101 through 1395w-154 — is delivered through private insurance plans (either standalone Prescription Drug Plans or Medicare Advantage plans with drug coverage) that compete for enrollees, with premiums, formularies, and cost-sharing structures varying significantly by plan and location. The national base beneficiary premium for 2026 is approximately $36–40/month (varying by plan), but actual premiums range from near-zero for low-cost plans to $200+/month for premium plans with more comprehensive drug coverage. High-income enrollees pay an Income-Related Monthly Adjustment Amount (IRMAA) surcharge ranging from $12.90 to $81.00/month (2026) based on 2024 income — the Part D IRMAA applies to individuals with MAGI above $106,000 (single) or $212,000 (married). The Low-Income Subsidy (LIS/Extra Help) program eliminates or significantly reduces premiums and cost-sharing for approximately 14 million low-income Medicare beneficiaries who qualify — providing essentially free drug coverage for those at or below 150% of the federal poverty level. The Inflation Reduction Act's $2,000 out-of-pocket cap (effective 2025) reshaped Part D's cost structure, while the IRA's drug price negotiation provisions (allowing CMS to negotiate prices for high-cost drugs) are beginning to affect which drugs are on formulary and at what cost-sharing tier — with the first 10 negotiated drugs taking effect in 2026.
Current Law (2026)
Medicare Part D provides outpatient prescription drug coverage through private plans. Premiums, formularies, and cost-sharing vary by plan.
| Parameter | 2026 Value (est.) |
|---|---|
| Average monthly premium | ~$40/month |
| Base beneficiary premium | ~$35 |
| IRMAA surcharge | $0-$81/month (income-based) |
| Late enrollment penalty | 1% of base premium per month of delay |
| Creditable coverage | Employer/union drug plans can serve as alternative |
Legal Authority
- 42 U.S.C. § 1395w-101 — Eligibility, enrollment, and information (Part D voluntary prescription drug benefit)
- 42 U.S.C. § 1395w-102 — Prescription drug benefits (standard benefit structure, deductible, coverage phases)
- 42 U.S.C. § 1395w-113 — Premiums, late enrollment penalty, and plan approval (base beneficiary premium, risk adjustment)
- 42 U.S.C. § 1395w-114 — Premium and cost-sharing subsidies for low-income individuals (Extra Help / Low-Income Subsidy)
How It Works
Part D operates as an annual marketplace where dozens of competing plans are available in each geographic region, with different formularies, premiums, deductibles, and pharmacy networks. The only way to know whether a specific plan covers your drugs — and at which cost-sharing tier — is to use the Medicare Plan Finder at medicare.gov/plan-compare, enter each medication by name, and compare total estimated annual out-of-pocket costs across available plans. Formularies and premiums change every year. The Inflation Reduction Act's benefit redesign eliminated the "donut hole" coverage gap and capped annual true out-of-pocket costs at $2,000 effective 2025; see Medicare Part D OOP Cap for the full benefit structure and monthly payment smoothing option.
High-income enrollees pay an IRMAA surcharge on top of their plan premium under 42 U.S.C. § 1395w-113 — the same MAGI thresholds that trigger the Part B IRMAA also trigger Part D IRMAA, adding $12.90–$81.00/month (2026) for individuals with income above $106,000 or couples above $212,000. IRMAA is based on income from two years prior (2024 income determines 2026 IRMAA). If your income dropped significantly due to retirement, job loss, or a life-changing event, you can appeal using Form SSA-44.
The late enrollment penalty is 1% of the national base beneficiary premium per month you went without creditable prescription drug coverage — applied permanently to your premium for life. A 24-month gap adds approximately 24% to your base premium every month going forward. Enrolling during your Initial Enrollment Period avoids this. If you maintain employer coverage past 65, confirm annually in writing that coverage is "creditable" — employers must send creditable coverage notices by October 14 each year. Save those letters; you'll need documentation when you eventually enroll in Part D.
How It Affects You
If you're approaching Medicare eligibility — enroll on time, the penalty is permanent: If you miss your Initial Enrollment Period (the 7-month window: 3 months before, the month of, and 3 months after your 65th birthday) without creditable prescription drug coverage, you'll pay a permanent Part D late enrollment penalty of 1% of the national base premium per month of delay. A 24-month gap adds approximately 24% to your base premium — every month, for the rest of your life. If you're keeping employer coverage past 65, get written confirmation from your employer every year that coverage is "creditable" (actuarially equivalent to Part D) — employers must send a creditable coverage notice annually by October 14. Save those letters; Social Security requires documentation when you eventually enroll. Note: if your employer plan is NOT creditable (some HRAs and certain mini-med plans fail this test), enroll in Part D immediately or face the penalty.
If your income is higher and you're seeing IRMAA surcharges: Part D IRMAA adds $12.90 to $81.00/month (2026) on top of your plan premium, based on your 2024 modified adjusted gross income. The first surcharge bracket hits at $106,000 (single) or $212,000 (married filing jointly); the maximum surcharge kicks in above $500,000 (single) or $750,000 (married). IRMAA is recalculated each year based on your income from two years prior — so the Part D IRMAA you pay in 2026 reflects your 2024 return. If your income dropped significantly in 2024 or 2025 due to retirement, a job loss, divorce, or death of a spouse, you can appeal IRMAA using Form SSA-44 (Medicare Income-Related Monthly Adjustment Amount — Life-Changing Event). File with your local Social Security office and include documentation of the qualifying event (retirement letter, divorce decree, spouse's death certificate). SSA can recalculate your IRMAA based on current or estimated income rather than the two-year-old figure. Call 1-800-772-1213 or visit your local SSA office to start the appeal.
If you take expensive specialty medications: The Inflation Reduction Act's $2,000 annual out-of-pocket cap (effective January 2026) is the most significant Part D change in the program's history. Your exposure on covered drugs is capped at $2,000 regardless of what the drugs cost — including specialty biologics, cancer drugs, and diabetes medications. The first 10 Medicare-negotiated drugs took effect January 1, 2026 — including apixaban (Eliquis), empagliflozin (Jardiance), rivaroxaban (Xarelto), sitagliptin (Januvia), and others — at prices 38–79% below prior list prices. To find the best plan for your specific drug list: go to medicare.gov/plan-compare, enter your ZIP code, add each of your drugs by name, and compare total estimated annual costs (premium + deductible + your cost-sharing) side by side. Plans that had your drug on Tier 3 (preferred brand) may have moved it to Tier 2 or added it to a specialty tier — the only way to know is to look up your specific plan's current formulary. The difference between a well-matched plan and a poorly-matched plan for your drug list is frequently $1,000–3,000/year. If your drugs cost more than $2,000 annually in out-of-pocket costs, you can also elect the Medicare Prescription Payment Plan (M3P) to spread your out-of-pocket costs evenly across monthly payments rather than paying large amounts in January when annual deductibles reset.
If you're enrolled in Part D — review your plan every Open Enrollment (October 15 – December 7): Part D plan formularies and premiums change annually, and your plan is required to send you an Annual Notice of Change by September 30 each year listing every formulary and cost-sharing change for the coming year. Read it. A drug on Tier 2 last year may move to Tier 3 or Tier 5 specialty this year — or be removed from the formulary entirely. Go to medicare.gov/plan-compare, enter all your drugs, and get a total annual cost estimate across every plan available in your area. Take 20–30 minutes each October; the difference between the best and worst plan for your specific drug list is commonly $500–2,000/year. If you switch plans during Open Enrollment, the new plan takes effect January 1.
If your income is below 150% FPL: You likely qualify for Extra Help (the Low-Income Subsidy, or LIS) — and if you're not enrolled, you're leaving money on the table. Extra Help pays most or all of your Part D premium and reduces drug copays to $4.90 for generic / $11.20 for brand-name drugs (2026 amounts). Full Extra Help is available to individuals with income at or below 150% FPL — approximately $21,870/year single or $29,580/year for a couple (2026). Apply at ssa.gov/extrahelp or call 1-800-772-1213; the SSA application typically takes 15–20 minutes and eligibility is retroactive to the month you apply. If you're already on Medicaid (including Medicaid-Medicare dual eligibles), you're automatically enrolled in the full LIS — you should be paying no more than the copay amounts above. If you're being charged more, contact your State Health Insurance Assistance Program (SHIP) for help correcting enrollment errors. Find your local SHIP at shiphelp.org or call 1-877-839-2675.
Implementing Regulations
- 42 CFR Part 423 — Voluntary Medicare prescription drug benefit (§§ covering Part D plan premiums, low-income premium subsidy, late enrollment penalty, income-related premium adjustment, payment to plans)
Pending Legislation (119th Congress)
- HR2340 — Advancing Enrollment and Reducing Drug Costs Act (Rep. Pappas, D-NH) — Automatically gives Medicaid expansion enrollees below 200% FPL access to Part D low-income subsidies (Extra Help), reducing premiums and copays
- S526 — Pharmacy Benefit Manager Transparency Act (Sen. Grassley, R-IA) — Forces PBMs to disclose fees, bans hidden markups and arbitrary clawbacks, requires annual reporting to FTC and HHS, adds whistleblower protections
- S1587 — Fair Prescription Drug Prices for Americans Act (Sen. Hawley, R-MO) — Caps U.S. drug list prices to the average in six reference countries; would reduce Part D plan costs
- S641 — Safe and Affordable Drugs from Canada Act (Sen. Klobuchar, D-MN) — Lets individuals import drugs from certified Canadian pharmacies for personal use
- HR 8143 — Would require PDP sponsors of a prescription drug plan under Part D to provide certain information. Status: Introduced.
Recent Developments
- IRA $2,000 out-of-pocket cap took effect January 2026: The Inflation Reduction Act's $2,000 annual out-of-pocket cap on Part D prescription drugs became effective for 2026 plan year — the most significant beneficiary protection added to Part D since the program launched in 2006. Previously, beneficiaries in the catastrophic phase paid 5% of drug costs with no cap; the new cap eliminates catastrophic cost-sharing entirely. Approximately 3.2 million beneficiaries who spent more than $2,000 on Part D drugs in 2025 will see direct savings. The cap also includes a new "smoothing" option allowing beneficiaries to spread out-of-pocket costs evenly across the year rather than paying large upfront amounts at the pharmacy.
- IRA drug negotiation — first negotiated prices in effect (2026): CMS's first round of Medicare drug price negotiations set Maximum Fair Prices for 10 drugs effective January 1, 2026. The negotiated prices — ranging from 38% to 79% below list price for drugs including eliquis (apixaban), jardiance, xarelto, januvia, and others — directly reduce Part D premiums by reducing plan costs for these high-utilization drugs. CMS projects the first round of negotiations will save Part D approximately $6 billion over 10 years. Plans must include negotiated drugs on their formularies at no more than the Maximum Fair Price.
- Plan premium stabilization and benchmark changes: Average Part D basic premium is approximately $46.50/month in 2026, slightly below 2025 levels — reflecting the partial impact of drug negotiation savings and plan competition. The premium stabilization program (ARPA-funded) that subsidized premiums through 2025 has expired, so plans with higher drug costs have increased premiums modestly. Low-Income Subsidy (LIS/Extra Help) beneficiaries — approximately 13 million people — continue to have their premiums covered fully if they choose a benchmark plan; the LIS benchmark increased to approximately $39.60/month in 2026.
- GLOBE model and international reference pricing risk: CMS proposed the Global Benchmark for Efficient Drug Pricing (GLOBE) model in December 2025, which would test international reference pricing for certain Part D drugs under the CMS Innovation Center authority. If finalized and implemented, GLOBE would set Medicare payment for selected drugs at a percentage of international prices (similar to the Most Favored Nation model attempted and vacated in 2021). Drug manufacturers and Part D plans have raised concerns that GLOBE would disrupt formulary design and plan bids for 2027 and beyond.