Call Us

Understanding Medicare Part D Costs

What are the costs of a prescription drug coverage plan?

Reviewed by: Brett Braithwaite, Licensed Insurance Agent.

Key Takeaways

  • The cost for a Part D plan varies depending on your needs, policy, and financial assistance. The premium can range from $13.20 up to $100+ depending on deductiblesA deductible is the amount you pay out of pocket before your insurance company covers its portion of your medical bills. For example: If your deductible is $1,000, your insurance company will not cover any costs until you pay the first $1,000 yourself. and drug coverage.

  • Your income can affect your premium, known as the income-related monthly adjustment amount (IRMAA).

  • If you go 63 days or more without creditable drug coverage after your Initial Enrollment Period,The initial enrollment period is a seven-month enrollment period when individuals, who are not automatically enrolled in Medicare, can sign up for Parts A and B. The period begins three months before your 65th birthday month, includes your birthday month, and continues for three months following your 65th birthday month. you may have to pay a late enrollment penalty.The Medicare Part D late enrollment penalty is a fee added onto your Part D premium if you go 63 consecutive days after your Initial Enrollment Period ends without creditable prescription drug coverage, and you want to enroll in Part D. The penalty generally applies for the lifetime of your Part D plan.

Senior couple looking into the distance while walking along the shore.

What is Medicare Part D?

Medicare Part D is a medication insurance program administered through private insurance companies. It’s essential to know Part D has:

  • different levels of coverage and costs.
  • a specific list of drugs available for each plan.
  • a list of in-networkIn-network refers to the doctors, hospitals and other providers that are inside of your provider network. This is the group of providers that has agreed with your health insurance company to treat its customers. pharmacies that you are required to use after enrollment.

How Much is Medicare Part D?

You pay a monthly premium for prescription drug coverage in addition to your Medicare Part B premium. The average Part D premium in 2020 is $32.741, [1] though the cost can vary with different plans.

Part D costs depend on:

  • The prescription drugs you need
  • The plan you join 
  • Whether you use a pharmacy in your plan’s network
  • Whether the drugs you use are on your plan’s formulary
  • Whether you’re eligible for Extra Help (a financial assistance program)

Other costs to consider:

  • Medicare Part D monthly premiums
  • Medicare Part D annual deductibles
  • CopaymentsA copayment (copay) is the fixed amount you pay directly to your provider for medical services or prescription drugs covered in your plan. For example: If your plan includes a copayment of $20 for office visits, you'll pay $20 to your doctor whenever you have an appointment. or co-insuranceCoinsurance is the percentage of your medical costs that you pay after you meet your deductible. The remaining amount is paid by your insurance company. For example: If you have a $1,000 medical bill and your coinsurance is 20%, you'll pay $200. Your insurance company will cover the final $800.
  • Late enrollment penalty

Is the Medicare Part D Premium Based on Income?

Your income plays a role in determining your Part D premium. You’re required to pay more for your prescription drug plan if you made more than $87,000 as an individual or $170,000 as a couple when filing your most recent tax return. The calculation is known as the income-related monthly adjustment amount (IRMAA).Income-Related Monthly Adjustments determine the premium costs for Medicare Part B and Part D based on your income. If you have a higher income and are enrolled in Medicare Part B or D, you are likely to have higher premiums. The IRMAA amounts change each year. 

The IRMAA rates for 2020 are listed below:

Individual: up to $87,000
Joint: up to $174,000
You pay (in addition to premium): $0

Individual: $87,000-$109,000
Joint: $174,000-$218,000
You pay (in addition to premium): $12.20

Individual: $109,000-$136,000
Joint: $218,000-$272,000
You pay (in addition to premium): $31.50

Individual: $136,000-$163,000
Joint: $272,000-$326,000
You pay (in addition to premium): $50.70

Individual: $163,000-$500,000
Joint: $326,000-$750,000
You pay (in addition to premium): $70.00

Individual: $500,000 and above
Joint: $750,000 and above
You pay (in addition to premium): $76.40 [2]

How Does Medicare Part D Work?

Medicare Part D plans have different levels of “tiers,”Drug tiers are the categories health insurance companies use to categorize the prescription drugs they cover. The tiers typically range from One to Five. Tier one is the lowest and usually includes the least expensive generic drugs. Tier Five includes specialty drugs that are usually very expensive, and some carriers include a Sixth Tier. which determines the cost of certain prescription drugs on the plan’s formulary list.A Prescription Drug Formulary is a list of all the prescription drugs covered by your health insurance. These drugs can be name brand or generic and are broken up into four categories for pricing. Medications that fall into the first tier have the lowest copays or copayments. The price goes up with each tier.  

  • Tier 1 has the lowest copay for generic drugs. To receive approval from the Food and Drug Administration, generic drug makers must prove that their product performs the same way as the corresponding brand name drug. Generic drugs use the same active ingredients as brand name drugs to achieve desired results.
  • Tier 2 has a medium copay for preferred brand name drugs. Preferred brand name drugs are medications manufactured by one manufacturer that are typically lower-cost among all brand name drugs. This is partly because these medications have been in the market for some time and are widely accepted).
  • Tier 3 has a higher copay for preferred brand and non-preferred brand name drugs. Non-preferred brand name drugs, on the other hand, tend to cost more because they are new to the market. You may have heard the term “designer drugs.” These high-cost drugs fall into the same category.
  • Tier 4 has a higher copay for non-preferred brand drugs and non-preferred generic drugs.
  • Tier 5, or the Specialty Tier, has the highest copay. It contains very high cost brand and generic drugs, which may require special handling and/or close monitoring.

Medicare Part D Payment Stages

There are four stages of costs for Medicare Part D. You’re responsible for paying different amounts in each stage.

  1. Stage 1 annual deductible
  2. Stage 2 initial coverage
  3. Stage 3 coverage gap, or “donut hole”
  4. Stage 4 catastrophic coverage.

Stages of Medicare Part D

Scroll to see more

Scroll to see more

Scroll to see more

Scroll to see more

Stage 1

Stage 2

Stage 3

Stage 4

What Does It Mean for You?

You pay 100% of prescription drug costs until you reach a certain amount set by your plan.


The maximum deductible for 2020 is $435. However, some plans don’t have a deductible. If that’s the case, you will skip the first phase and start in initial coverage.

You pay a portion of the costs through co-insurance or co-pays, while your Part D plan pays the rest. The tier usually determines the price of your prescription drug.

You can’t be charged more than 25% of your medications’ retail cost, which is likely more than you paid in the initial coverage stage.


Before 2006, Medicare beneficiaries were responsible for 100% of their drug costs after reaching their initial coverage limit.


You pay whichever is higher: 5% of costs for your covered drugs, or $3.60 for generic drugs/$8.95 for brand-name drugs.

When Do You Move to the Next Stage?

This phase continues until you reach your deductible. Then, you move into the initial coverage stage.

Initial coverage continues until you and your insurance carrier reach $4,020 in 2020. Then, you move into the coverage gap stage.

The coverage gap continues until you’ve spent $6,350 out-of-pocket in 2020. Then, you move into the catastrophic coverage stage.

Catastrophic coverage continues until the end of the year. Then, you will return to the deductible stage on January 1.

What’s an Example?

  • Your annual deductible: $400
  • Retail medication cost: $250
  • You pay: $250

You’ll need to spend $150 more to reach your deductible.

  • Retail medication cost: $100
  • Your plan pays: $70
  • Your co-pay: $30
  • Retail medication cost: $400
  • Your plan pays: $300
  • You pay 25%: $100
  • Retail medication cost $500
  • Your plan pay 95%s: $475
  • You pay 5%: $25

How Much is the Lifetime Late Enrollment Penalty?

You should be aware of Medicare Part D’s lifetime late enrollment penalty if you miss the Initial Enrollment Period. The penalty applies if you go for more than 63 days after your Initial Enrollment Period without creditable drug coverage.

The late enrollment penalty cost is calculated by Medicare when you enroll in a Part D plan. To calculate the penalty,  multiply 1% of the yearly average premium (which is $32.74 in 2020) by the number of eligible months you did not have Part D insurance. Then, you round to the nearest ten cents. 

Example: Let’s say your Initial Enrollment Period ended March 31, 2018. You waited until December 2019 to join a Part D plan during the Open Enrollment Period. Your policy went into effect on January 1, 2020, which means you went 21 months without creditable coverage.

Here’s how to calculate the penalty:

.21 (multiply 1% by the number of months you went without coverage even though you were eligible to enroll) X $32.74 (2020 average Part D premium) = $6.90 ($6.88 before rounding to the nearest $.10)

The cost of the penalty can change if the national premium average increases or decreases. A late enrollment penalty can remain in effect as long as your Part D plan is active.

Do you have more questions about enrollment and how to avoid the penalty? Check out our guide on how to navigate Medicare Part D enrollment.

Are There Financial Assistance Options for Part D?

Medicare offers a program called Extra Help to assist with Part D costs for those with limited income and resources. Extra Help is estimated to be worth $5,000 per year. [3] If you qualify, the program helps cover your premiums, deductibles and co-insurance costs.


Extra Help Eligibility

To qualify for Extra Help, a person must be receiving Medicare, have limited resources and income, and reside in one of the 50 States or the District of Columbia. If you’re not sure if you are eligible based on income or resources, you can apply.

Ways you can automatically qualify for Extra Help:

  • You already qualify for Medicare and MedicaidMedicaid is a state-based health insurance program based on an individual's financial needs. 
  • You are enrolled in a Medicare Savings Program 
  • You already receive Supplemental Security Income (SSI) benefits

You’re eligible for Extra Help if both apply:

  • Your resources are limited to $14,610 for individuals or $29,160 for couples. Resources include savings, investments, real estate outside of a primary residence, stocks and more.
  • Your annual income is limited to $19,140 for individuals or $25,860 for couples.

How to Apply for Extra Help

If you don’t automatically qualify but meet the limited requirements listed above, you can apply for Extra Help online, by telephone (1-800-772-1213) or by visiting your local Social Security office. You will need bank account statements, investment statements, stock certificates, tax returns, pension award letters and payroll slips.


What if I don’t qualify for Extra Help?

If you don’t qualify for Extra Help, you are required to pay your plan’s monthly premium, a yearly deductible (if your policy has one), and the copays or co-insurance of your drug coverage. However, you do have the right to appeal. You can also re-apply if your income and resources change.

Ways to Lower Your Costs:

  • Switch to less expensive or generic drugsGeneric drugs are prescription drugs that have the same active ingredients as brand-name drugs, but usually cost less. 
  • Look into your state’s Medicaid or State Health Insurance Assistance Program (SHIP) programs

How can I avoid paying a late enrollment penalty?

When you first become eligible, joining a prescription drug plan is the easiest way to avoid receiving a late enrollment penalty. Even if you don’t need drug coverage at the time, it could save you a significant amount of money if your circumstances change.

Another way to avoid the penalty is by having creditable prescription drug coverage. Your employer or a union usually provides these plans, and they should cover the same costs as Medicare Part D. You won’t have to pay the penalty if you decide to switch to a Part D plan later.

Can I keep my Medigap policy with Plan D?

It depends. If you enroll in a Part D plan with Original Medicare, you can keep your Medigap plan. But if you join a Medicare Advantage Plan that includes Part D, you will need to cancel your Medigap policy.  You cannot have more than one active plan at a time.

What's Next?