How Medication Refill Dates and Days Supply Are Estimated
Learn how to use the Refill Calculator, understand its assumptions and interpret the estimate.
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How to use this calculator
Open the Refill Calculator and enter values using the units shown.
Formula and assumptions
The calculator uses the visible formula and the assumptions you enter. It does not silently retrieve private records or guarantee a real-world outcome.
Worked example
A quantity of 60 taken as one unit twice daily gives an estimated 30-day supply.
Related calculators and guides
Important limitations
This calculator performs date and quantity math only. Actual refill availability depends on the prescription, prescriber, pharmacy, insurer, medication type and applicable rules.
Disclaimer
Educational planning tool only. Do not change, stop or ration medication based on this estimate. Confirm refill timing with a pharmacist or prescriber.
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Frequently Asked Questions
- What does the Refill Calculator calculate?
- Estimate medication days of supply, expected run-out date and a reminder date from quantity, daily use and a planning buffer.
- Can I change the assumptions?
- Yes. Enter values that match your situation and review the displayed assumptions and limitations before using the result.
- Is the result guaranteed?
- No. The result is an estimate and should be independently verified before any medical, legal, financial, academic, engineering or purchasing decision.
Last updated 7/22/2026