Prescription Run-Out Date Calculator
Last reviewed: July 2026
Estimate when a prescription supply may run out from the fill date and days supplied. This is basic date math for planning only, not medical, dosing, insurance, or dispensing advice.
Enter supply details
Estimated run-out date
Oct 10, 2026
28 day(s) from today based on the values entered.
This calculator estimates a run-out date using basic days-supply math. It does not tell you whether to take more or less medication or whether a refill can be processed.
Run-out date formula
Estimated run-out date = fill date + days supplied. If the fill date counts as Day 1, the calendar offset is days supplied minus one. For example, a 30-day supply filled on June 1 runs through about June 30 when the fill date counts as Day 1.
Worked run-out date examples
These examples show how the estimated run-out date shifts with the days supplied and the counting method. They are planning estimates only.
| Supply | Fill date | Counting method | Estimated run-out |
|---|---|---|---|
| 30-day supply | June 1 | Day 1 = fill date | around June 30 |
| 30-day supply | June 1 | Day after fill | around July 1 |
| 60-day supply | June 1 | Day 1 = fill date | around July 30 |
| 90-day supply | June 1 | Day 1 = fill date | around Aug 29 |
Who uses a run-out date calculator
Patients on maintenance medication who want to know when a 30-day or 90-day supply runs out so they can plan a refill or a pharmacy trip before running short.
Caregivers and travelers coordinating multiple prescriptions, mail-order timing, or a trip who need to confirm supplies last through a specific date.
Run-out date questions
How do I calculate a prescription run-out date?
Add the days supplied to the fill date. If the fill date counts as Day 1, the calendar offset is days supplied minus one. For example, a 30-day supply filled on June 1 runs out around June 30. This tool does the date math for you.
What is a medication run-out date?
A run-out date is the estimated day your current supply of a medication is used up, based on the fill date and the number of days the prescription was written to last. It is a planning estimate, not a dosing instruction.
Does the fill date count as day one?
It depends on how you count. Many people count the fill date itself as Day 1, which makes the run-out date fall on the fill date plus days supplied minus one. Toggle the option in the calculator to match how your pharmacy counts.
How is a run-out date different from a refill date?
A run-out date estimates when a supply is fully used. A refill date estimates when you may be able to refill early, often at 75% to 90% of the supply used. Use the prescription refill date calculator for refill timing and the days supply calculator to confirm how long a quantity should last.
Can I estimate the run-out date for a 90-day supply?
Yes. Enter the fill date and 90 as the days supplied. A 90-day supply filled on the first of a month typically runs out about three months later, near the end of that period, depending on how the fill date is counted.