Prescription Refill Calculator
Result
Prescription Refill Date Calculate prescription refill date. Formula: Refill Date = Last Fill + (Quantity / Daily Dose). Shows when medication runs out. Educational reference. — free online calculator.
Formula
- Prescription Refill Calculator calculates its result from Last fill date, Quantity dispensed, Prescribed units per day. It uses the formula Days supply = quantity ÷ prescribed daily use; refill date = last-fill date + days supply.. Change any input to recalculate the result instantly. This is an informational calculation and is not medical advice.
- The main inputs are Last fill date, Quantity dispensed, Prescribed units per day. Enter them in the units and format shown in the calculator.
- Use the measurement units shown beside each field. The result is an estimate and should be interpreted in context.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Prescription Refill
- Last fill date: 2026-10-01
- Quantity dispensed: 30
- Prescribed units per day: 1
Using Last fill date = 2026-10-01, Quantity dispensed = 30, Prescribed units per day = 1, the calculated result is Days supply: 30 | Estimated run-out date: 2026-10-31.
Sample result: Calculating…
Frequently asked questions
What does the Prescription Refill calculate?
Prescription Refill Date Calculate prescription refill date. Formula: Refill Date = Last Fill + (Quantity / Daily Dose). Shows when medication runs out. Educational reference. — free online calculator.
Which values should I enter?
Enter Last fill date, Quantity dispensed, Prescribed units per day using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Days supply = quantity ÷ prescribed daily use; refill date = last-fill date + days supply..
Why might my result differ from another source?
Results can differ because measurement methods, rounding and assumptions vary. This calculator is an estimate and is not a medical diagnosis.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.