The short answer
Compare costs over the same period, using the days supplied that your pharmacist confirms. Thirty tablets do not necessarily mean a 30-day supply. Ask whether a longer fill is appropriate and covered.
Quantity and days supplied are different
Quantity is the number of units dispensed. Days supplied describes how long those units last under the prescribed instructions. Do not infer one from the other, and do not change how you take medication to make a price comparison work.
Compare an equal period
If the prescription and your plan allow it, request a 30-day quote and a 90-day quote. Compare three 30-day totals with one 90-day total, including repeated delivery charges. For example, three $12 fills cost $36; one $30 fill costs $6 less for the same period. These are illustrative numbers.
Consider the practical tradeoffs
A larger fill costs more upfront and may be less useful if the prescription changes. Confirm refill timing, storage requirements, and plan limits with your pharmacist. The calculator’s annual figure is only a multiplication of unchanged costs.
Common questions
Is 90 days always a better value?
No. Compare the real totals and whether that supply length is appropriate for your prescription.
Sources & further reading
Source links checked 2026-09-22. Cost information only; this content has not been clinically reviewed.