Should I Enroll in Medicare Part D? (w/Examples) + FAQs

Yes, you should enroll in Medicare Part D — even if you take few or no prescription drugs right now. Under 42 U.S.C. § 1395w-113(b), Medicare imposes a permanent late enrollment penalty of 1% of the national base beneficiary premium for every full month you go without creditable prescription drug coverage after your Initial Enrollment Period ends. That penalty never goes away — it follows you for as long as you have Part D coverage.

Around 11% of Medicare beneficiaries currently lack creditable drug coverage, putting them at risk of paying hundreds or even thousands of dollars in penalties over their lifetime. As of 2025, 54.8 million out of 68.8 million Medicare beneficiaries are enrolled in a Part D plan.

Here’s what you’ll learn in this article:

  • 💊 How the Part D late enrollment penalty works and exactly how much it could cost you every month for life
  • 🛡️ When you can safely skip Part D without getting penalized — and the one document that proves it
  • 💰 How the Inflation Reduction Act’s $2,100 out-of-pocket cap protects you from catastrophic drug costs in 2026
  • 📋 Real-world examples and scenarios showing who benefits most (and who pays the price for waiting)
  • 🏛️ State programs like New York’s EPIC and Pennsylvania’s PACE that wrap around Part D to slash your costs even further

What Medicare Part D Actually Covers

Medicare Part D is a voluntary outpatient prescription drug benefit provided through private insurance companies that contract with the federal government. You can get Part D coverage in two ways: a stand-alone Prescription Drug Plan (PDP) that pairs with Original Medicare, or a Medicare Advantage plan with drug coverage (MA-PD) that bundles everything together. Both types must meet minimum coverage standards set by CMS.

Every Part D plan must cover drug classes spanning all disease states, with at least two chemically distinct drugs in each class. Plans must also cover all drugs in six “protected” classes: immunosuppressants, antidepressants, antipsychotics, anticonvulsants, antiretrovirals, and antineoplastics. Starting in 2026, Part D plans must also cover all 10 drugs selected for Medicare drug price negotiation under the Inflation Reduction Act.

For 2026, 360 stand-alone PDPs will be offered by 17 different parent organizations across 34 PDP regions nationwide. That’s a 22% decrease from 2025 — and nearly half as many as 2024. Medicare Advantage drug plans, on the other hand, continue to expand, and 58% of Part D enrollees now get drug coverage through MA-PD plans.

How the Three Coverage Stages Work in 2026

The Part D benefit has three stages that determine what you pay out of pocket at any given time. Understanding these stages is critical because your costs change as you move through them during the calendar year.

The Deductible Stage

You pay 100% of your drug costs until you meet the annual deductible, which can be up to $615 in 2026. Some plans offer a lower deductible or no deductible at all, but no plan can charge more than $615. Certain plans exempt low-cost generics from the deductible entirely, meaning you’d pay a copay for those drugs right away.

The Initial Coverage Stage

After you meet your deductible, you pay 25% coinsurance for both generic and brand-name drugs. Your plan pays the other 75%. You stay in this stage until your total out-of-pocket spending on covered Part D drugs reaches $2,100 in 2026.

The Catastrophic Coverage Stage

Once you hit the $2,100 out-of-pocket cap, you pay $0 for covered Part D drugs for the rest of the year. Your plan covers 100% of costs from that point forward. This hard cap on spending was introduced by the Inflation Reduction Act starting in 2025 at $2,000, and it increased to $2,100 for 2026.

Coverage StageWhat You Pay in 2026
Deductible100% of drug costs, up to $615 max
Initial Coverage25% coinsurance until $2,100 out-of-pocket
Catastrophic Coverage$0 — plan covers everything

The Part D Late Enrollment Penalty That Never Goes Away

The single biggest reason to enroll in Part D — even if you take zero medications — is the late enrollment penalty. This penalty is permanently added to your monthly Part D premium if you go 63 or more consecutive days without Medicare drug coverage or other creditable coverage after your Initial Enrollment Period ends.

How CMS Calculates the Penalty

Medicare multiplies 1% of the “national base beneficiary premium” by the number of full, uncovered months you were eligible but didn’t enroll. For 2026, the national base beneficiary premium is $38.99 per month. The result is rounded to the nearest $0.10 and added to your monthly premium.

The national base beneficiary premium can increase each year, which means your penalty amount can also go up each year — even though the number of uncovered months stays the same. You pay this penalty for as long as you have Part D coverage. It does not expire.

A Real Penalty Calculation

Frank, age 70, became eligible for Medicare in May 2022 but didn’t enroll in Part D. He had no creditable drug coverage for 43 months. When he finally enrolled during the Annual Enrollment Period in late 2025 (with coverage starting January 2026), his penalty was 43% of $38.99, which equals roughly $16.76. Rounded to the nearest $0.10, Frank pays an extra $16.80 every single month — on top of his regular plan premium — for life.

Months Without CoverageMonthly Penalty Added (2026)
12 months$4.70
24 months$9.40
36 months$14.00
43 months$16.80
60 months$23.40

When You Can Safely Skip Part D Without a Penalty

Not everyone needs to rush into Part D. You can delay enrollment without penalty if you have “creditable” prescription drug coverage from another source. Creditable coverage means the other plan’s actuarial value equals or exceeds the actuarial value of standard Part D coverage.

Sources of Creditable Coverage

Common sources include employer or union-sponsored group health plans, TRICARE, the Federal Employees Health Benefits Program (FEHBP), and Veterans Affairs (VA) drug coverage. Your employer or plan sponsor is required to send you a notice before October 15 each year telling you whether your prescription drug coverage is creditable or non-creditable.

Keep this notice. It is your proof that you had creditable coverage. If you lose it and later enroll in Part D, you may have difficulty proving you shouldn’t owe a late enrollment penalty. CMS may assess the penalty unless you can document your prior coverage.

The IRA’s Impact on Creditable Coverage Status

The Inflation Reduction Act’s $2,000 out-of-pocket cap (now $2,100 in 2026) changed the math for employer plans. Because Part D’s actuarial value increased, some employer plans that were previously creditable may now fall below the threshold. If your employer’s plan flips from creditable to non-creditable, they must notify you within 30 days. Pay close attention to these notices — a status change means you need to enroll in Part D during the next available enrollment period or face the penalty.

The Six Enrollment Periods You Need to Know

Timing is everything with Part D. You can only enroll during specific windows, and missing them can be costly. There are six types of election periods.

Initial Enrollment Period (IEP)

This is a seven-month window surrounding your 65th birthday: the three months before your birthday month, your birthday month, and three months after. This is the best time to enroll because it prevents gaps in coverage and avoids the late enrollment penalty entirely. Missing this window without creditable coverage starts the penalty clock.

Annual Enrollment Period (AEP)

Runs from October 15 through December 7 every year. During this window, you can join a Part D plan for the first time, switch plans, or drop your current plan. Changes made during the AEP take effect January 1 of the following year.

Special Enrollment Periods (SEPs)

SEPs let you make changes outside the normal windows due to qualifying events. These include moving out of your plan’s service area, losing creditable coverage, qualifying for Extra Help (Low-Income Subsidy), entering or leaving a nursing home, or being a member of a State Pharmaceutical Assistance Program like New York’s EPIC.

Medicare Advantage Open Enrollment Period (MA OEP)

Runs from January 1 through March 31 each year. This period is only for people already enrolled in a Medicare Advantage plan. You can switch to a different MA plan, or drop your MA plan and return to Original Medicare with a stand-alone Part D plan. You can make only one change during this window.

Enrollment PeriodWhen It Happens
Initial Enrollment Period (IEP)7-month window around your 65th birthday
Annual Enrollment Period (AEP)October 15 – December 7, every year
Special Enrollment Periods (SEPs)Varies based on qualifying life event
MA Open Enrollment PeriodJanuary 1 – March 31, every year

How the Inflation Reduction Act Changed Part D

The Inflation Reduction Act of 2022 made the most significant changes to Part D since the program launched in 2006. These changes directly affect whether and how much you benefit from enrolling.

The $2,100 Out-of-Pocket Cap

Before the IRA, there was no hard cap on Part D out-of-pocket spending. Beneficiaries in the catastrophic phase still paid 5% coinsurance — which could mean thousands of dollars a year for people on expensive specialty drugs. The IRA eliminated that 5% coinsurance in 2024 and set a firm annual spending cap of $2,000 in 2025, rising to $2,100 in 2026.

This cap applies to both stand-alone PDPs and drug coverage in MA-PD plans. For people taking expensive brand-name medications, this single change can save thousands of dollars per year. Before the IRA, annual out-of-pocket costs for specialty oral anticancer medications alone ranged from $11,143 to $20,592.

The $35 Insulin Cap

Part D plans must now cap insulin copays at $35 per month, regardless of the insulin product or which coverage stage you’re in. This took effect in 2023. For the roughly 3.3 million Medicare beneficiaries who use insulin, this change alone can save hundreds of dollars annually.

Free Vaccines

All adult vaccines covered under Part D are now available at no cost to beneficiaries. Before the IRA, beneficiaries could face significant cost-sharing for Part D vaccines like the shingles vaccine, which can cost over $200 per dose.

Medicare Drug Price Negotiation

The IRA authorized the federal government to negotiate prices for high-cost Medicare drugs for the first time. Negotiated prices for the first 10 Part D drugs take effect on January 1, 2026. These include medications for diabetes, heart disease, blood clots, and other common conditions.

The Medicare Prescription Payment Plan

Starting in 2025, beneficiaries can opt into the Medicare Prescription Payment Plan to spread out-of-pocket costs into equal monthly installments across the calendar year. This plan doesn’t lower your total drug costs — it smooths them. Instead of facing a $2,100 bill in January, you could pay as little as $167 per month throughout the year.

Three Real-World Scenarios: Who Should Enroll and Why

Scenario 1: Maria, 65, Healthy and on No Medications

Maria just turned 65 and takes no prescription drugs. She’s tempted to skip Part D because she doesn’t want to pay a monthly premium for something she isn’t using. But skipping Part D is a gamble. If Maria waits even three years to enroll, she’ll owe a penalty of roughly $14 per month for the rest of her life — on top of her regular premium.

A low-cost Part D plan might charge $10–$15 per month. Paying that now protects Maria from a permanent penalty that could far exceed the premiums she would have paid.

Maria’s ChoiceFinancial Outcome
Enrolls at 65 in a $12/month planPays $144/year in premiums, $0 penalty
Waits 3 years, then enrollsPays $14/month penalty plus plan premium — permanently
Waits 5 years, then enrollsPays $23.40/month penalty plus plan premium — permanently

Scenario 2: James, 67, Takes Three Brand-Name Drugs for Chronic Conditions

James has Type 2 diabetes, high blood pressure, and high cholesterol. He takes insulin, an ACE inhibitor, and a statin — all brand-name versions. Before the IRA, James could have paid well over $5,000 a year out of pocket. Under the 2026 Part D benefit, his insulin is capped at $35/month, and his total out-of-pocket spending across all drugs is capped at $2,100.

James also enrolls in the Medicare Prescription Payment Plan, spreading his costs into monthly installments instead of paying large sums at the start of the year. His monthly drug costs become predictable and manageable.

James’s Cost FactorWhat He Pays in 2026
Insulin (per month)$35 max
Total annual out-of-pocket$2,100 max
Monthly with Payment Plan~$175/month spread evenly

Scenario 3: Linda, 63, Has Employer Coverage and Is Approaching 65

Linda works full-time and has prescription drug coverage through her employer. Her employer has notified her that the plan is creditable. Linda does not need to enroll in Part D right now. She can safely delay enrollment without penalty as long as her employer coverage remains creditable.

When Linda retires and loses her employer coverage, she’ll qualify for a Special Enrollment Period to join Part D. The key is that Linda must keep her creditable coverage notice from her employer as proof. Without it, CMS could charge her the late enrollment penalty.

Linda’s SituationWhat She Should Do
Employer plan is creditableDelay Part D — no penalty
Employer plan becomes non-creditableEnroll in Part D during next AEP or SEP
Loses employer coverage at retirementUse SEP to enroll in Part D immediately

Mistakes That Can Cost You for Life

Enrollment errors with Part D don’t just cause temporary inconvenience — they create permanent financial consequences. These are the most common mistakes people make and why they matter.

Assuming You Don’t Need Part D Because You’re Healthy

Health changes are unpredictable. A cancer diagnosis, a fall, or a new chronic condition can create a sudden need for expensive medications. If you delayed enrollment and have no creditable coverage, you’ll pay the late enrollment penalty for life on top of the cost of drugs you now desperately need.

Ignoring Your Employer’s Creditable Coverage Notice

Your employer sends a creditable coverage notice before October 15 each year for a reason. If you throw it away and your plan is actually non-creditable, the clock on your penalty starts ticking without your knowledge. By the time you realize the mistake, you could owe years’ worth of penalty.

Missing the 63-Day Window

You have a 63-day grace period after losing creditable coverage. If you go even one day past 63 days without creditable coverage, the penalty starts accumulating. Mark your calendar the day you lose coverage.

Not Reviewing Your Plan During Annual Enrollment

Part D formularies, copays, and premiums change every year. A drug that was covered on your plan’s formulary in 2025 might not be covered in 2026. Failing to compare plans during the AEP (October 15 – December 7) can leave you paying full price for medications your plan no longer covers.

Confusing Medicare Advantage Drug Coverage With Stand-Alone Part D

If you’re enrolled in a Medicare Advantage plan with drug coverage (MA-PD), you already have Part D. You cannot also enroll in a stand-alone PDP. If you enroll in a stand-alone PDP while in an MA plan, you’ll be disenrolled from your MA plan and returned to Original Medicare — which may not be what you intended.

Part D Premiums, Costs, and Income-Based Surcharges

What You’ll Pay for a Stand-Alone PDP in 2026

The 2026 Part D base beneficiary premium is $38.99 per month, but this is a national average — not what you’ll actually pay. Actual PDP premiums range from $0 to over $100 per month depending on your region and plan. Most MA-PD enrollees pay no additional premium beyond their Part B premium because MA plans can use rebate dollars to eliminate Part D costs.

A Part D premium stabilization demonstration is also moderating premium increases in 2026. The Trump administration reduced the monthly premium subsidy from $15 to $10 for 2026 and raised the limit on monthly premium increases to $50.

If your modified adjusted gross income exceeds $106,000 for individuals or $212,000 for couples, you’ll pay a Part D income-related surcharge on top of your plan premium. This surcharge ranges from $13.70 to $85.80 per month depending on your income bracket. About 8% of Part D enrollees pay this surcharge.

Do’s and Don’ts of Part D Enrollment

DoDon’t
Enroll during your IEP to avoid any penaltyDon’t assume you’ll never need prescription drugs
Keep every creditable coverage notice your employer sendsDon’t throw away coverage notices — they’re your proof
Compare plans every year during AEP (Oct 15 – Dec 7)Don’t auto-renew without checking formulary changes
Check if your drugs are on a plan’s formulary before enrollingDon’t pick a plan based only on the lowest premium
Enroll in the Medicare Prescription Payment Plan if you have high costsDon’t ignore the option to spread costs monthly
Ask your employer if your coverage is creditable before turning 65Don’t assume employer coverage is always creditable
Use your SEP promptly if you lose employer coverageDon’t let more than 63 days pass without creditable coverage

Pros and Cons of Enrolling in Part D

ProsCons
Avoids the permanent late enrollment penalty that increases your premium for lifeMonthly premiums add a recurring cost even if you take no medications
Out-of-pocket spending is capped at $2,100 in 2026 under the IRADeductible can be up to $615 before the plan starts paying
Insulin capped at $35/month; adult vaccines are freeFormularies change yearly — your drug might not be covered next year
Medicare Prescription Payment Plan lets you spread costs monthlyThe Payment Plan smooths costs but doesn’t reduce total spending
Access to negotiated drug prices starting in 2026 for 10 drugsHigh-income earners pay an IRMAA surcharge of up to $85.80/month
Extra Help program covers premiums and copays for low-income beneficiariesThe number of available stand-alone PDPs is shrinking each year
Protection against unpredictable future drug costsPlans use prior authorization and step therapy that can delay access

How Extra Help and Low-Income Subsidies Work

Medicare’s Extra Help program (also called the Low-Income Subsidy, or LIS) pays Part D premiums, deductibles, and copays for eligible beneficiaries. To qualify, your income must be below 150% of the federal poverty level ($23,475 for individuals or $31,725 for married couples in 2025) and your assets must be below $17,600 for individuals or $35,130 for couples.

As of May 2025, 13.9 million Part D enrollees receive Extra Help. Beneficiaries who qualify for Medicaid, Medicare Savings Programs, or Supplemental Security Income automatically qualify. Others must apply through the Social Security Administration.

A critical benefit of Extra Help: if you qualify, you do not pay the late enrollment penalty — even if you delayed enrollment. The IRA also expanded full LIS eligibility in 2024 to include beneficiaries with incomes between 135% and 150% of the federal poverty level, a group that previously received only partial subsidies.

State Programs That Wrap Around Part D

Several states run State Pharmaceutical Assistance Programs (SPAPs) that work alongside Part D to further reduce drug costs. These programs don’t replace Part D — they supplement it. SPAP contributions may even count toward your Part D out-of-pocket limit.

New York’s EPIC Program

New York’s Elderly Pharmaceutical Insurance Coverage (EPIC) program helps low-to-moderate-income seniors age 65 and older pay for prescriptions. EPIC operates as a Medicare wraparound program: Part D pays first, then EPIC covers remaining costs. The program has two tiers — the Fee Plan and the Deductible Plan — based on income.

EPIC also covers drugs that Part D excludes, such as prescription vitamins and cough/cold preparations. EPIC members get a Special Enrollment Period each year to change Part D plans outside the normal AEP — a benefit most Part D enrollees don’t have.

Pennsylvania’s PACE Program

Pennsylvania’s PACE (Pharmaceutical Assistance Contract for the Elderly) and PACENET programs serve residents age 65 and older with limited incomes. Like EPIC, these programs coordinate with Part D to reduce out-of-pocket costs. Eligibility is based on income, and the programs cover copays and other expenses Part D doesn’t fully pay.

PACE (Program of All-Inclusive Care for the Elderly)

Don’t confuse Pennsylvania’s PACE with the federal PACE program — the Program of All-Inclusive Care for the Elderly. Federal PACE covers all Medicare and Medicaid services, including prescription drugs, for frail seniors who qualify for nursing home care but want to stay at home. If you join PACE, you get your Part D drugs through the program. Joining a separate Part D plan while enrolled in PACE will disenroll you from the program.

How Part D Interacts With Medicare Advantage

More than half of Part D enrollees — 58% in 2025 — get drug coverage through a Medicare Advantage plan rather than a stand-alone PDP. MA-PD plans bundle hospital, medical, and prescription drug coverage into one plan.

Most MA-PD enrollees pay no additional premium for drug coverage because plan sponsors use federal rebate dollars to subsidize or eliminate the Part D premium. The average monthly drug premium in MA-PDs is roughly $7, compared to $39 for stand-alone PDPs. But MA-PD plans have experienced bigger increases in deductibles and coinsurance rates since the IRA took effect. Mean deductibles in MA plans jumped from $66 in 2024 to $228 in 2025, and the share of beneficiaries facing coinsurance for brand-name drugs rose from 2.5% to 27.7%.

If you’re in an MA-PD plan and want to switch to Original Medicare with a stand-alone PDP, you can do so during the MA Open Enrollment Period (January 1 – March 31). You can only make one change during this window.

Part D Forms and the Enrollment Process Step by Step

CMS updated the standard Part D enrollment form effective January 1, 2026. Here’s what you’ll encounter.

Personal Information Section

You’ll provide your name, date of birth, Medicare Beneficiary Identifier (MBI), address, phone number, and email. Double-check your MBI — an incorrect number can delay enrollment.

Current Coverage Questions

The form asks whether you currently have prescription drug coverage through an employer, union, TRICARE, VA, or other source. If you do, you must indicate whether that coverage is creditable. This is where your employer’s creditable coverage notice matters. Marking your coverage as creditable when it’s not — or vice versa — can trigger penalty disputes later.

Payment and Premium Options

You’ll choose how to pay your monthly premium: bank account deduction, credit/debit card, mailed bill, or Social Security withholding. If you choose Social Security withholding, it can take up to 3 months to start. During that gap, your plan will bill you directly.

Medicare Prescription Payment Plan Opt-In

The form now includes an option to enroll in the Medicare Prescription Payment Plan, which lets you spread your out-of-pocket costs across monthly installments instead of paying large lump sums early in the year.

Low-Income Subsidy / Extra Help Section

If you believe you qualify for Extra Help, you can indicate that on the form. CMS will verify your eligibility. You can also apply separately through the Social Security Administration.

How Part D Spending and Financing Works Behind the Scenes

Medicare’s actuaries estimate that Part D benefit spending will total $141 billion in 2026, representing 11% of all Medicare benefit spending. Funding comes from three sources: federal government contributions (75%), beneficiary premiums (13%), and state contributions (12%).

The IRA dramatically shifted who bears the cost of high drug spending. Before 2025, Medicare’s reinsurance payments covered 80% of catastrophic drug spending. Now, Medicare covers only 20% for brand-name drugs and 40% for generics above the catastrophic threshold. Part D plans and drug manufacturers now shoulder a much larger share. This shift explains why some plans have increased deductibles and coinsurance — they’re absorbing costs that Medicare previously covered.

For 2026, Medicare will pay Part D plans an average of $1,710 per enrollee in direct subsidy payments, plus $522 in reinsurance payments and $1,337 in LIS subsidy payments per low-income enrollee.

Key Organizations and Entities That Shape Part D

Centers for Medicare & Medicaid Services (CMS) administers the Part D program, sets annual benefit parameters, and oversees plan compliance. CMS also manages the creditable coverage rules and late enrollment penalty calculations.

Part D Plan Sponsors are private insurance companies (like UnitedHealthcare, Humana, CVS/Aetna) that offer PDPs and MA-PDs. They submit bids to CMS, design formularies, negotiate drug prices with manufacturers, and contract with pharmacies.

Pharmacy Benefit Managers (PBMs) sit between plans, manufacturers, and pharmacies. They negotiate manufacturer rebates, manage formularies, and influence which drugs your plan covers and at what cost. The IRA’s restructuring of Part D may lead PBMs and plans to impose more administrative hurdles like prior authorization before covering higher-cost therapies.

The Social Security Administration (SSA) processes applications for Extra Help and handles IRMAA determinations for higher-income beneficiaries.

State Health Insurance Assistance Programs (SHIPs) provide free, personalized counseling to help Medicare beneficiaries compare Part D plans, understand their options, and navigate enrollment.

FAQs

Can I enroll in Part D at any time during the year?

No. You can only enroll during specific periods: your Initial Enrollment Period, the Annual Enrollment Period (October 15 – December 7), or a Special Enrollment Period triggered by a qualifying event.

Do I need Part D if I have VA drug coverage?

No. VA drug coverage is considered creditable. You can delay Part D without a penalty as long as your VA coverage continues.

Is the Part D penalty really permanent?

Yes. The penalty is added to your premium for as long as you have Part D coverage. It does not expire, even if you switch plans.

Does the $2,100 out-of-pocket cap include my premium?

No. The cap only counts deductibles, copays, and coinsurance you pay for covered Part D drugs. Premiums are separate.

Can I have both a Medicare Advantage plan and a stand-alone Part D plan?

No. If you enroll in a stand-alone PDP while in an MA plan, you’ll be disenrolled from Medicare Advantage and returned to Original Medicare.

Does Extra Help eliminate the late enrollment penalty?

Yes. If you qualify for Extra Help, you don’t pay a late enrollment penalty even if you delayed enrollment.

Will my Part D premium go up if I earn more money?

Yes. If your income exceeds $106,000 (individual) or $212,000 (couple), you’ll pay an income-related surcharge of $13.70 to $85.80 per month.

Can my employer’s coverage change from creditable to non-creditable?

Yes. The IRA’s improvements to Part D raised its actuarial value, which means some employer plans may no longer qualify as creditable. Your employer must notify you within 30 days of any change.

What is the Medicare Prescription Payment Plan?

Yes, it’s a real program. It lets you spread your Part D out-of-pocket costs into equal monthly payments across the year, but it doesn’t reduce your total costs.

Are all Part D plans the same?

No. Plans differ in premiums, deductibles, formularies, pharmacy networks, and cost-sharing requirements. Compare plans annually using Medicare’s Plan Finder tool.