How to Compare Part D Plans: Total Yearly Cost, Not Just the Premium

The drug plan with the lowest premium is not always the plan that costs you least. A low premium can sit next to high copays for the drugs you take each month. A higher premium can sit next to low copays that save you far more over a year. The sound way to compare plans is to add up the full year: premiums, the deductible, and what you pay for your own drugs, month by month. This guide shows that count, step by step, with the set 2026 figures. Our Paying for Care section holds more guides on drug costs and help with them.

The four parts of your yearly cost

Add those four parts for your own drug list. That total is the number to compare, not the premium alone.

• The premium. This is the monthly charge to hold the plan. Multiply it by 12 to get its yearly weight.
• The deductible. In 2026 the standard deductible can be as high as $615 (Ledger A9). You pay the full cost of your drugs until you meet it, unless your plan waives it or covers some drugs before it.
• The copays and shares. After the deductible, you pay a set copay or a share of the cost for each drug. Each plan puts drugs into tiers. A drug on a low tier costs you less than the same drug on a high tier in a different plan.
• The cap. Your own payments for covered drugs stop at $2,100 in 2026 (Ledger A10). Past that point, covered drugs cost you $0 for the rest of the year.

Why the same drug costs a different amount in each plan

Plans build their own drug lists. One plan may place your drug on a low tier with a small copay. The next plan may place the same drug on a high tier with a share of a high price. A third plan may not list the drug at all. If a plan does not list your drug, you can face the full price, or you may need to ask for an exception.

Pharmacy choice matters too. Many plans charge less at a pharmacy they name as preferred. The same drug, in the same plan, can cost more at a store down the road. Check the store you use in each plan you price.

Our guide on Part D in 2027 covers next year's deductible and cap. Our guide on Extra Help in 2027 explains the program that cuts drug costs for people with low income.

A worked way to count the year

Take one drug you use each month and price it in two plans.

Now add 12 months of premiums to 12 months of drug costs in each plan. In many such counts, the plan with the higher premium wins by a wide margin. The premium is the part you see in an ad. The drug costs are the part you pay at the counter, month after month.

Watch the cap as you count. If your drug costs are high, you may reach the $2,100 cap (Ledger A10) part way through the year. Past that month, your covered drugs cost $0. A plan that gets you to the cap at a lower total spend can be the cheaper plan even if its early months cost more.

• Plan one charges a low premium. Your drug sits on a high tier. You pay a large share each month, and you meet a $615 deductible first (Ledger A9).
• Plan two charges a higher premium. Your drug sits on a low tier with a small set copay. Its deductible is lower, or it covers your drug before the deductible.

Who pays for what

• Your Part D plan pays its share of your covered drug costs after you meet the deductible, based on its tiers and rules.
• Medicare pays a large share of plan costs in the last phase of the year, after you pass the $2,100 cap (Ledger A10). Your cost for covered drugs in that phase is $0.
• Medicaid and the Extra Help program can cut premiums and copays for people who qualify. Our guide on checking Medicare Savings Programs and Extra Help in this section explains both.
• Private pay covers the rest: your premium, your deductible up to $615 (Ledger A9), your copays, and the full price of any drug your plan does not cover.

Sample situation

May takes two drugs each month. Plan A charges the lower premium, but it puts her main drug on a high tier, so she pays a large share each month after a $615 deductible (Ledger A9). Plan B charges $20 more a month in premium, but it puts that drug on a low tier with a small copay. May adds up both years in full. Plan B costs her less over the year by far, even though its premium is higher. She joins Plan B in the fall window, and it starts January 1 (Ledger B4).

Steps to compare plans this fall

• List every drug you take, with the dose and how often you take it.
• Enter that list in the plan compare tool at Medicare.gov, with the pharmacy you use.
• For each plan, note the premium times 12, the deductible, and the yearly drug total the tool shows.
• Add the premium total and the drug total. Compare that sum across plans.
• Check that each plan lists your drugs, and note the tier for each one.
• Send your choice in time for the plan to get it by December 7 (Ledger B4).