How to Compare Prescription Costs Fairly
Comparing price per fill is misleading when the fills last different lengths of time. A $30 mail-order fill that lasts 90 days is cheaper than a $15 retail fill that lasts 30. The fair way is to compare the cost over the same period:
Cost over a period = Fills needed × Cost per fill
Fills needed = Days in the period ÷ Days per fill (rounded up)
The calculator does this for up to four options at once and also shows the cost per day, which is the simplest single number for comparing.
Example: Retail vs Mail Order vs Discount Card
| Option | Per fill | Fills a year | Per year |
|---|---|---|---|
| Retail 30-day copay | $15.00 | 13 | $195.00 |
| Mail order 90-day | $30.00 | 5 | $150.00 |
| Discount card cash price (30-day) | $11.50 | 13 | $149.50 |
Thirteen 30-day fills are needed in a year, not twelve, because 12 × 30 is only 360 days. That extra fill is why monthly costs often run higher than expected.
Ways People Lower Their Prescription Costs
- 90-day fills. Many plans charge less per day for 90 days, especially at preferred or mail-order pharmacies. They're usually for long-term medications. See the 90-day refill calculator.
- Generic or lower-tier alternatives. Ask your prescriber or pharmacist whether a generic or a preferred drug on your plan's list would work for you.
- Pharmacy choice. Prices vary a lot between pharmacies, and plans often have preferred pharmacies with lower copays.
- Discount cards and cash prices. For some generics, the cash price with a free discount card is lower than a copay.
- Manufacturer copay cards. For brand-name drugs with commercial insurance, these can lower your cost significantly.
- Assistance programs. Medicare Extra Help (the Low-Income Subsidy), state pharmaceutical assistance programs and manufacturer patient assistance programs can help if cost is a barrier.
Important Rules Before You Switch
- Cash doesn't count toward your deductible. Discount-card and cash purchases usually don't count toward your insurance deductible or out-of-pocket maximum. For an expensive medication, paying through insurance may cost less over the whole year even if one fill costs more.
- Copay cards and government insurance don't mix. Federal law doesn't allow manufacturer copay coupons with Medicare, Medicaid or other government coverage.
- Copay accumulator programs. Some commercial plans don't count copay-card payments toward your deductible, so costs can jump mid-year when the card's limit runs out. Check your plan documents.
- Medicare Part D cap. In 2026, out-of-pocket spending on covered Part D drugs is capped at $2,100 a year (up from $2,000 in 2025). Once you reach it, covered drugs cost nothing for the rest of the year. Medicare also offers the Prescription Payment Plan to spread these costs into monthly payments.
Copays, Coinsurance and Deductibles in Plain Terms
- Copay: a fixed amount per fill, such as $10.
- Coinsurance: a percentage of the drug's price, such as 25%. To compare, multiply the price by the percentage and enter the result as the cost per fill.
- Deductible: what you pay before the plan starts sharing costs. If you have one, compare the prices you pay after it's met, or run the calculator twice for before and after.
Your plan's online drug price tool, or a quick question to your pharmacist, will give you accurate prices to enter. If a prior authorization is holding up coverage, see the prior authorization timeline calculator.