Medication Schedule End Date Calculator
Work out the day a supply of medication runs out from the quantity, doses per day, and when you start.
How it works
daily use = amount per dose × doses per day · days of supply = ⌊quantity ÷ daily use⌋ · last day = start + days − 1
A medication supply lasts as many whole days as the quantity divided by how much you take each day, rounded down so you never plan on a partial final day. Counting from the first dose date, the last fully covered day is the start plus that many days minus one, and the reorder reminder builds in a few days so a refill arrives before you run out. This is a planning aid for stock and refills, not dosing advice.
Worked example
30 tablets at 1 tablet twice a day is 2 a day, so 30 ÷ 2 = 15 days of supply. Starting September 16, 2026, the last full day is September 30, and you should reorder by about October 1.
Frequently asked questions
Why round the days down?
Rounding down means the last counted day is one you can fully cover. A remainder that is less than a full day’s dose would leave you short, so it is not counted as a supply day.
What does the reorder date do?
It subtracts a three-day buffer from the run-out date so a refill has time to be filled and collected before your current supply ends. Adjust your own ordering earlier if your pharmacy is slower.
Is this medical advice?
No. It is a scheduling and refill-planning tool. Always follow the dosing on your prescription label and check with your pharmacist or doctor about timing and refills.
Related calculators
Educational scheduling tool only — follow your prescription and pharmacist’s instructions, not this estimate.