What is Medicare Part D? (Prescription drug coverage)
Part D is Medicare's prescription drug benefit. Created in 2003, transformed by the Inflation Reduction Act of 2022. Starting 2025, there's a $2,100 annual out-of-pocket cap for the first time ever. Insulin is capped at $35 a month. ACIP-recommended adult vaccines are free. Smoothing lets you spread drug costs across the year in monthly installments. Big improvements — but you still need a plan, and signing up at first eligibility is the cheapest path.
Dr. Ed Weir, PhD · 20 years inside Social Security · "Former" Sergeant, USMC
Updated April 2026
What is Medicare Part D? (Prescription drug coverage)
Medicare Part D is the prescription drug benefit. Private plans deliver it under federal contract with CMS. Sign up at first eligibility — even if you take no drugs now — or face a permanent late-enrollment penalty. The 2026 annual out-of-pocket cap is $2,100. Extra Help (LIS) makes Part D nearly free if your income is below 150% FPL of the federal poverty level.
This whole page is about Medicare Part D
Free plan comparison from licensed Medicare advisors
Chapter Medicare is a free service with licensed advisors who run the official Medicare Plan Finder against your medication list and pharmacy preferences. They are one of our trusted partners at 24Help. Tell them Dr. Ed sent you.
Here's what to do about Part D.
Part D rewards people who sign up on time and punishes people who don't. Here's the order of operations.
1. Sign up at first eligibility — even if you take no drugs
Your Initial Enrollment Period for Part D is the same 7-month window as the rest of Medicare — the 3 months before your 65th birthday month, your birthday month, and the 3 months after.
Here's the deal: even if you take zero medications today, signing up for the cheapest available standalone Part D plan now is almost always cheaper than the permanent late-enrollment penalty later. The penalty is 1% of the national base beneficiary premium per month you went without creditable coverage — added to your premium for life.
Sign up for Part D › ›2. Use the official Plan Finder before AEP
Medicare.gov Plan Finder is the official tool for comparing every Part D plan available in your ZIP code. Run it once a year before AEP (Oct 15 – Dec 7) — even if you're already enrolled. Plans change every year. Formularies drop drugs, copays move, pharmacies join and leave networks.
Log all your medications with exact dosage and your preferred pharmacy. The tool will show your projected annual cost across plans. That's the honest comparison.
Medicare.gov Plan Finder › ›3. Apply for Extra Help if you may qualify
Extra Help — also called the Low Income Subsidy (LIS) — drops Part D costs to near zero for people whose income is below 150% of the federal poverty level. As of 2024, the IRA expanded full Extra Help to everyone under that line.
Extra Help also waives the Part D late-enrollment penalty entirely if you're eligible. Apply through SSA on Form SSA-1020 — online, by phone, or on paper. No fee. No catch.
Apply for Extra Help (SSA-1020) › ›4. Cold-call Part D solicitation is illegal — hang up
If a stranger calls, texts, or knocks at your door pitching a Medicare plan, hang up. CMS Medicare Communications and Marketing Guidelines (MCMG) prohibit unsolicited Medicare plan contact. The legitimate places to compare plans are Medicare.gov Plan Finder, your state SHIP counselor, or a licensed agent you contacted first.
20 years at SSA taught me this — Medicare scams spike during AEP. The script always sounds official. The pressure is always urgent. Hang up and report it to 1-800-MEDICARE.
Report Medicare fraud › ›2026 Part D numbers worth knowing
Which of these fits your situation?
Part D looks the same on the outside for everyone. What changes is your situation — drugs, employer coverage, income, timing. Pick what fits.
I take no prescriptions — do I still need Part D?Yes — the cheapest plan now beats the permanent penalty later
Yes. Sign up at first eligibility even if your medicine cabinet is empty.
The Part D late-enrollment penalty is 1% of the national base beneficiary premium per full month you went without creditable drug coverage — added to your premium permanently. Wait 5 years, that's 60% on top of every premium for life. Pick the cheapest available standalone plan during your IEP and you're insured against both surprise prescriptions and the LEP.
The cheapest available Part D plan now is almost always cheaper than the permanent late-enrollment penalty later. The LEP follows you for life — it does not reset. Sign up.
I have employer, VA, Tricare, or FEHB drug coverageMay count as creditable — but you have to confirm in writing
If your existing drug coverage is at least as good as standard Part D, it's called "creditable coverage" — and you can delay Part D without the LEP. VA, Tricare, FEHB, Indian Health Service, and most active-employer drug plans count.
Every year, your plan must mail you a Notice of Creditable Coverage. Save it. If your coverage ends, you have a 63-day window to enroll in Part D before the LEP starts ticking. Lose track of that 63-day clock and the penalty is permanent.
If your other coverage ends, you have 63 days to enroll in Part D. Miss it and the late-enrollment penalty is permanent.
I want to know how the IRA changed Part DFive real changes — OOP cap, insulin, vaccines, smoothing, negotiation
The Inflation Reduction Act of 2022 is the biggest Part D overhaul since the program began. Five concrete changes:
One — a $2,100 annual out-of-pocket cap for 2026, the first hard ceiling Part D has ever had. Two — insulin capped at $35 a month, since January 2023. Three — ACIP-recommended adult vaccines (shingles, RSV, Tdap) cost $0 under Part D, since January 2023. Four — the Medicare Prescription Payment Plan, also called "smoothing," lets you spread your drug costs across the year in monthly installments starting 2025. Five — Medicare can negotiate prices on the most expensive drugs, with the first 10 negotiated prices effective in 2026.
You don't apply for any of these. The OOP cap, the insulin cap, and free vaccines apply to every Part D plan automatically. Smoothing you have to opt into.
Money is tight — my drugs are expensiveMultiple programs may bring the cost to near zero
Three layers worth checking. First — Extra Help (LIS) drops Part D premium, deductible, and copays to near zero for people under 150% of the federal poverty level. Apply through SSA. Second — most states run a State Pharmaceutical Assistance Program (SPAP) for additional help on top of Medicare. Third — drug manufacturers run patient assistance programs for many brand-name medications.
The new $2,100 annual out-of-pocket cap also caps your worst-case Part D exposure for the year, no matter what plan you have.
Which combination of help programs is right for you depends on your income, state, and medications. Your state SHIP counselor can sort through them for free — they don't sell anything.
My pharmacy doesn't take my planNetworks change every year — you have options
Part D plans use pharmacy networks. Some pharmacies are "preferred" (lowest copays), some are "standard" (higher copays), and some are out of network entirely. Networks change every plan year.
Your options: switch to a pharmacy that's in network, use the plan's mail-order option for 90-day fills (often the cheapest path for maintenance medications), or wait until AEP (Oct 15 – Dec 7) and switch to a plan whose network includes your pharmacy. Don't switch outside AEP unless you have a Special Enrollment Period.
The right move depends on your medications, your pharmacy preferences, and your travel patterns. Run the official Plan Finder or get free unbiased help from your state SHIP counselor.
I'm choosing between standalone Part D and a Medicare Advantage drug plan (MAPD)Both legitimate — the right choice depends on your situation
If you have Original Medicare, you add a standalone Part D plan. If you have Medicare Advantage, drug coverage is usually built in (called MAPD).
This isn't actually a Part D decision — it's a Medicare path decision. Once you pick Original Medicare or Medicare Advantage, your Part D options follow. The path itself has tradeoffs: networks, referrals, doctor access, Medigap eligibility down the road. That's a bigger conversation than just drug coverage.
The Original-Medicare-vs-Medicare-Advantage decision is genuinely consequential and harder to reverse than people realize. Get unbiased help from your state SHIP counselor or a licensed Chapter Medicare advisor before you choose.
I missed my IEP and now I have a Part D late-enrollment penaltyYou may be able to appeal — and Extra Help waives it entirely
Two paths. First — you can appeal an LEP determination through C2C Innovative Solutions, the CMS contractor that handles Part D LEP reconsiderations. The appeal asks them to recalculate your gap, especially if you had creditable coverage they didn't credit you for.
Second — if you qualify for Extra Help (LIS), the LEP is waived entirely while you're enrolled. Income under 150% of the federal poverty level. That's the cleanest path out of an LEP if you're income-eligible.
Extra Help (LIS) doesn't just lower your Part D costs — it waives the late-enrollment penalty entirely. If you may qualify, apply now. The penalty disappears the month your Extra Help starts.
I'm helping a parent with their drug coverageBystander — here's the most useful thing you can do
If you're helping a parent navigate Part D, sit down with them and run Medicare.gov Plan Finder together. Pull up every prescription bottle in the house and enter the exact drug name, dose, and frequency. Pick the local pharmacy they actually use.
Also watch for Extra Help eligibility — income under 150% FPL gets them near-zero Part D costs and waives any late-enrollment penalty. And one more thing: if anyone calls them about a Medicare plan they didn't ask for, hang up. CMS prohibits cold-call Medicare solicitation. Scammers prey on older Americans during AEP.
If a stranger calls your parent pitching a Medicare plan — hang up. CMS rules prohibit it. Report it to 1-800-MEDICARE.
Part D rarely stands alone — here's what pairs with it.
If you're on Part D, you may also qualify for programs that lower your drug costs, your premium, or both. Worth a 5-minute check.
Extra Help (Low Income Subsidy)
Extra Help drops Part D premium, deductible, and copays to near zero for people under 150% of the federal poverty level. As of 2024, the IRA expanded full Extra Help to everyone under that line. It also waives the Part D late-enrollment penalty entirely.
Medicare Savings Program (MSP)
Different lane than Part D — the Medicare Savings Program covers your Part B premium and may cover deductibles and copays. Many people qualify for MSP and Extra Help simultaneously. State Medicaid agencies administer MSP.
Medicare Prescription Drug Costs
Sister page to this one. Walks through what you actually pay under Part D — deductible, copays, the new $2,100 OOP cap, smoothing, the math behind the late-enrollment penalty.
Medicare Advantage Explained
Medicare Advantage (Part C) plans usually bundle Part D drug coverage. If you're choosing a path, the Medicare Advantage decision and the Part D decision are tied together — read both pages.
Medicare Late-Enrollment Penalty
Deep dive on the Part D late-enrollment penalty calculation, how Extra Help waives it, and how to appeal an LEP determination through C2C Innovative Solutions.
Medicare Annual Enrollment Period
AEP runs Oct 15 – Dec 7 every year. It's the standard window to switch Part D plans for the next plan year. Plans change annually — worth comparing in AEP even if you're already enrolled.
Everything people ask me
What is Medicare Part D?
Part D is the Medicare prescription drug benefit. Created by Congress in 2003 and rolled out in 2006, it's delivered by private insurance plans under contract with the federal government — not by Medicare directly.
You enroll in a separate standalone Part D plan if you have Original Medicare, or you get drug coverage built into a Medicare Advantage plan. Either way, the federal rules — formulary protections, the $2,100 out-of-pocket cap, the $35 insulin cap, free ACIP vaccines — apply across every plan.
Do I need Part D if I take no medications?
Yes — sign up at first eligibility even if you take nothing right now.
The Part D late-enrollment penalty is 1% of the national base beneficiary premium per full month you went without creditable drug coverage after your IEP. It's permanent. Wait 5 years, that's 60% added to your premium for life. The cheapest available standalone plan during your IEP is almost always cheaper than the LEP later.
What is creditable drug coverage?
"Creditable coverage" is drug coverage that's at least as good as standard Medicare Part D. If you have it, you can delay Part D without the late-enrollment penalty.
Common sources: VA, Tricare, FEHB, Indian Health Service, and most active-employer drug plans. Every year your plan must mail you a Notice of Creditable Coverage. Save it. If your coverage ends, you have a 63-day window to enroll in Part D before LEP exposure starts.
What is the Part D late-enrollment penalty?
1% of the national base beneficiary premium for every full month you were without creditable drug coverage after your Initial Enrollment Period — added to your Part D premium permanently.
The national base beneficiary premium is set by CMS each year (currently around $38.99 for 2026). The penalty rounds to the nearest $0.10. Permanent means permanent — it does not reset, year over year. The two ways out: appeal through C2C Innovative Solutions if the gap was miscalculated, or qualify for Extra Help (LIS), which waives the LEP entirely.
What changed about Part D under the Inflation Reduction Act?
The IRA of 2022 is the biggest Part D overhaul since the program began. Five concrete changes:
First — a $2,100 annual out-of-pocket cap for 2026 (Section 11201). Second — insulin capped at $35 a month, since January 2023 (Section 11406). Third — ACIP-recommended adult vaccines (shingles, RSV, Tdap) cost $0 under Part D, since January 2023. Fourth — the Medicare Prescription Payment Plan ("smoothing") starting 2025, lets you spread your drug costs across the year (Section 11202). Fifth — Medicare drug price negotiation, with the first 10 negotiated prices effective in 2026 (Sections 11001–11003).
How do drug formularies and tiers work?
Every Part D plan has a formulary — the list of drugs it covers. Drugs are sorted into tiers (typically 5 or 6) that determine your copay or coinsurance. Tier 1 is generics with the lowest copay. Higher tiers are brand-name and specialty drugs with higher cost-sharing.
Formularies must cover at least two drugs in every therapeutic class. Six "protected classes" — antidepressants, antipsychotics, anticonvulsants, antiretrovirals, antineoplastics, and immunosuppressants — require nearly all drugs to be covered. If your drug isn't on the formulary, you can request a formulary exception.
What's the Part D smoothing payment plan?
It's officially called the Medicare Prescription Payment Plan (IRA Section 11202), but everyone calls it "smoothing." Starting 2025, you can opt in and your Part D plan spreads your drug copays across the year as monthly installments instead of charging the full amount at the pharmacy.
It doesn't lower your costs — the total annual amount is the same. It just smooths out the cash-flow shock if you have an expensive specialty drug. You opt in through your plan. Most useful for people who hit the $2,100 OOP cap early in the year.
Can I get help paying for Part D?
Yes — the program is called Extra Help, also known as the Low Income Subsidy (LIS). It drops Part D premium, deductible, and copays to near zero for people under 150% of the federal poverty level. The IRA expanded full Extra Help to everyone under that line as of 2024.
Extra Help also waives the Part D late-enrollment penalty entirely while you're enrolled. Apply through SSA on Form SSA-1020 — online, by phone, or on paper. No fee.
How do I pick a Part D plan?
Three free options. First — Medicare.gov Plan Finder is the official tool. Enter your medications, dosages, and pharmacy and it ranks every available plan by your projected annual cost. Second — your state SHIP counselor gives free, unbiased Medicare counseling. Third — Chapter Medicare provides free plan comparison from licensed Medicare advisors and is one of our trusted partners at 24Help.
All three are free and none of them sells you a specific plan. Use them.
What if I get a cold call about Part D?
Hang up. Cold-call solicitation for Medicare plans — calls, texts, door knocks — is prohibited under CMS Medicare Communications and Marketing Guidelines (MCMG). The legitimate places to find a plan are Medicare.gov Plan Finder, your state SHIP counselor, or a licensed agent you contacted first.
Report unsolicited Medicare calls to 1-800-MEDICARE or to the Senior Medicare Patrol in your state. Scams spike during AEP every year.
Sources
Every figure and rule on this page is verified against primary sources. Last verified 2026-04-27.
- The 2026 Medicare Part D annual out-of-pocket maximum is $2,100, established by Section 11201 of the Inflation Reduction Act of 2022 and indexed annually by CMS. —cms.gov(verified 2026-05-08)
- Adult vaccines recommended by the Advisory Committee on Immunization Practices (ACIP) are covered with $0 cost-sharing under Medicare Part D effective January 1, 2023, per the Inflation Reduction Act … —cms.gov(verified 2026-05-08)
- Section 11202 of the Inflation Reduction Act established the Medicare Prescription Payment Plan ("smoothing"), letting Part D enrollees opt to pay drug costs in monthly installments starting January … —cms.gov(verified 2026-05-08)
- Sections 11001–11003 of the Inflation Reduction Act authorize Medicare drug price negotiation. The first 10 negotiated drug prices take effect January 1, 2026; an additional 15 drugs were selected for … —cms.gov(verified 2026-05-08)
- The 2026 Medicare Part D national base beneficiary premium is $38.99 per month, set by CMS in the annual Part D rate announcement. —cms.gov(verified 2026-05-08)
- Creditable prescription drug coverage is coverage at least as good as standard Medicare Part D. Plan sponsors must provide a Notice of Creditable Coverage to Medicare-eligible enrollees annually … —cms.gov(verified 2026-04-28)
- Section 11404 of the Inflation Reduction Act of 2022 expanded full Low Income Subsidy (Extra Help) eligibility to individuals with incomes up to 150% of the federal poverty level, effective January 1, … —cms.gov(verified 2026-05-08)
- CMS Medicare Communications and Marketing Guidelines (MCMG) prohibit unsolicited contact with Medicare beneficiaries to market Medicare plans, including unsolicited phone calls, text messages, and … —cms.gov(verified 2026-04-28)
- Medicare Plan Finder at Medicare.gov is the official CMS tool for comparing Medicare Part D prescription drug plans available to a beneficiary by ZIP code. —medicare.gov(verified 2026-04-28)
- Medicare Part D was created by the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA), Public Law 108-173. —govinfo.gov(verified 2026-05-08)
- Medicare Part D is delivered by private prescription drug plans under contract with CMS, governed by 42 CFR Part 423. —ecfr.gov(verified 2026-04-28)
- Six protected drug classes under Medicare Part D — antidepressants, antipsychotics, anticonvulsants, antiretrovirals, antineoplastics, and immunosuppressants — require nearly all drugs in the class to … —ecfr.gov(verified 2026-04-28)
- Section 11406 of the Inflation Reduction Act of 2022 caps insulin cost-sharing under Medicare Part D at $35 per month per covered insulin product, effective January 1, 2023. —law.cornell.edu(verified 2026-05-08)
- Medicare Part D late-enrollment penalty is 1% of the national base beneficiary premium for each full month an eligible person was without creditable prescription drug coverage after their Initial … —law.cornell.edu(verified 2026-05-08)
- A break in creditable prescription drug coverage of 63 or more consecutive days after the Initial Enrollment Period triggers Part D late-enrollment penalty exposure. —law.cornell.edu(verified 2026-05-08)
- Medicare Part D late-enrollment penalty is waived for any month an enrollee qualifies for the Low Income Subsidy (Extra Help). —law.cornell.edu(verified 2026-05-08)
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Part D rules shift every year. CMS updates the OOP cap, the formulary protections, the smoothing rules. I'll send a plain-English note when something changes that matters to you.