When and how to sign up for Part D prescription drug coverage

You can enroll in Medicare Part D during your initial enrollment period, which starts three months before the month you turn 65 and lasts for seven months total. If you miss that window, you can still join during the general enrollment period (January 1 to March 31 each year), though you may pay a higher premium for each month you waited. You can also enroll if you experience a may have access to life event—such as losing employer coverage or moving to a new state—which opens a special enrollment period lasting 63 days.

To enroll, you contact a Part D plan directly, work with a Medicare counselor, or use Medicare.gov. You will need your Social Security number, Medicare card, and information about any prescriptions you currently take. Most plans process enrollment within one to two weeks, though coverage typically begins on the first day of the following month.

Key Takeaways

  • Your initial enrollment period lasts seven months, starting three months before you turn 65, and missing it can mean paying a permanent penalty on your premiums.
  • You can enroll through a Part D plan directly, by phone with Medicare at 1-800-MEDICARE, through a local State Health Insurance information Program (SHIP), or online at Medicare.gov.
  • Part D plans vary widely in which drugs they cover and what you pay, so comparing plans before you enroll helps you find one that matches your prescriptions and budget.
  • If you have limited income, you may be able to lower your Part D costs through the Low-Income Subsidy program, which you can learn about when you enroll.

Understanding your initial enrollment period and important date

Your initial enrollment period is a seven-month window that Medicare creates for you automatically. It begins three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your period runs from March through September. During this time, you can enroll in Part D without any penalty, even if you do not yet have Medicare Part B.

If you do not enroll during your initial period and you do not have other prescription drug coverage (such as through an employer or union), Medicare charges you a late enrollment penalty. This penalty is calculated as 1% of the national average Part D premium for each month you were not enrolled, and it stays on your premium for as long as you have Part D. For example, if you wait two years to enroll, you would pay roughly 24% more each month. The national average premium changes each year, so the dollar amount of your penalty changes too.

If you already have prescription drug coverage through an employer, retiree plan, or union, you may not need to enroll right away. However, you should check whether that coverage is "creditable"—meaning it is at least as good as Part D. Your employer or plan administrator can tell you this. If your coverage ends or you lose it, you then have 63 days to enroll in Part D without a penalty.

How to enroll through Medicare or a Part D plan

You have several ways to enroll. The most direct route is to visit Medicare.gov, click "Enroll in Medicare Part D," and compare plans side by side. You can enter your current prescriptions, and the tool will show you what each plan would cost you for those drugs. You can then enroll in a plan directly through the website.

You can also call Medicare at 1-800-MEDICARE (1-800-633-4227). Representatives are available seven days a week, and they can answer questions about plans, help you compare costs, and enroll you over the phone. If you are deaf or hard of hearing, you can use the TTY number 1-877-486-2048.

A third option is to contact a Part D plan directly. Insurance companies that offer Part D plans have their own enrollment lines and websites. You can find a list of plans available in your area on Medicare.gov, which includes each plan's phone number.

You can also work with a State Health Insurance information Program (SHIP). SHIP is a free counseling service in every state that helps people understand Medicare options. To find your state's SHIP, visit shiptalk.org or call 1-877-839-2675. SHIP counselors can explain plans, help you compare them, and guide you through enrollment without charge.

Comparing Part D plans and understanding costs

Part D plans are offered by private insurance companies, and each plan has its own list of covered drugs, called a formulary. One plan may cover your blood pressure medication at a low cost while another plan does not cover it at all, or covers it only if you try a different drug first. This is why comparing plans before you enroll matters—the difference in your out-of-pocket costs can be hundreds of dollars per year.

When you compare plans, you will see several cost pieces. The monthly premium is what you pay to the plan. The deductible is the amount you pay out of pocket before the plan starts to help pay for drugs. The copay or coinsurance is what you pay for each prescription after you have met your deductible. Most plans also have a coverage gap, sometimes called the "donut hole," where you pay a higher share of drug costs once you and your plan have spent a certain amount together. In 2024, that gap begins after combined spending reaches $5,850, though this threshold changes each year.

To compare plans, use the Medicare Plan Finder tool on Medicare.gov. Enter your prescriptions, and the tool will show you the total estimated cost for each plan for the year. You can sort by monthly premium, total cost, or pharmacy network. Many people find that the cheapest plan is not always the best plan—a plan with a higher premium might have lower copays for your specific drugs, saving you money overall.

What to do if you have limited income

If your income is below a certain level, you may be able to lower your Part D costs through the Low-Income Subsidy program, also called "Extra Help." This program helps pay your premiums, deductibles, and copays. Income limits vary by state and change each year, but in 2024 they are roughly 150% to 200% of the federal poverty level, depending on your household size and state.

To learn whether you may have access to, you can explore through Social Security, the Railroad Retirement Board, or your state Medicaid office. You can explore online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. The process process usually takes two to four weeks. Once you are approved, Social Security will send you a notice showing your subsidy amount, and you can use this information when you enroll in a Part D plan.

If you are already enrolled in a Part D plan when you learn about the subsidy, you can switch plans during the Low-Income Subsidy enrollment period, which runs from December 7 through February 7 each year. This allows you to choose a plan that works better with your subsidy.

Changing your Part D plan or coverage

Once you enroll in a Part D plan, your coverage begins on the first day of the following month. You are locked into that plan for the rest of the calendar year, with one exception: if you have the Low-Income Subsidy, you can switch plans between December 7 and February 7.

If you do not have the subsidy, you can change plans during the annual enrollment period, which runs from October 15 through December 7 each year. During this time, you can switch to a different Part D plan, and your new coverage will begin on January 1. You can also change plans if you experience a may have access to life event, such as moving out of your plan's service area, losing employer coverage, or becoming may be able to access for Medicaid. These special enrollment periods last 63 days from the date of the event.

If you want to drop Part D coverage entirely, you can do so during the annual enrollment period or if you gain other creditable prescription drug coverage. However, if you drop Part D and do not have other coverage, you will owe the late enrollment penalty if you rejoin later.

Understanding the Part D coverage stages

Part D coverage works in stages throughout the year. In the initial coverage stage, you pay your copay or coinsurance for each prescription until your combined spending (what you pay plus what the plan pays) reaches your plan's out-of-pocket limit. Once you reach that limit, you enter the catastrophic coverage stage, where the plan covers most of the cost of your drugs for the rest of the year.

Many plans also have a coverage gap between these stages. In the gap, you pay a higher share of the cost of brand-name and generic drugs. The exact amounts change each year. For example, in 2024, you pay 25% of the cost of brand-name drugs in the gap. Once your total out-of-pocket spending reaches a certain amount (around $8,850 in 2024), you move into catastrophic coverage.

Understanding these stages helps you predict what you will pay over the year. If you take many expensive medications, you might reach catastrophic coverage early and pay less overall. If you take fewer drugs, you might stay in the initial coverage stage all year. The Medicare Plan Finder tool estimates your costs for the full year, taking all stages into account.

Frequently Asked Questions

Can I enroll in Part D if I am still working and have employer drug coverage?

Yes, but you do not have to. If your employer coverage is creditable (as good as Part D), you can wait to enroll in Part D without a penalty. Ask your employer or plan administrator whether your coverage is creditable. If it is, you have 63 days after your coverage ends to enroll in Part D without a penalty.

What happens if I miss my initial enrollment period?

You can still enroll during the general enrollment period (January 1 to March 31), but you will pay a late enrollment penalty on top of your monthly premium. This penalty stays with you as long as you have Part D. You can also enroll if you experience a may have access to life event, such as losing other coverage or moving to a new state.

Do all Part D plans cover the same drugs?

No. Each plan has its own formulary, or list of covered drugs. One plan may cover your medication at a low cost while another does not cover it at all. This is why comparing plans using your actual prescriptions is important—it can save you hundreds of dollars per year.

Can I switch Part D plans after I enroll?

If you do not have the Low-Income Subsidy, you can switch plans only during the annual enrollment period (October 15 to December 7) or if you have a may have access to life event. If you have the Low-Income Subsidy, you can also switch between December 7 and February 7 each year.

What if I cannot afford my Part D copays?

If your income is low, you may be able to lower your costs through the Low-Income Subsidy program. You can explore through Social Security at ssa.gov or by calling 1-800-772-1213. Some pharmaceutical companies also offer patient information programs that help cover the cost of specific drugs.