How the refill date calculator works
- Supply length = quantity ÷ (tablets per dose × doses per day), rounded down to whole days.
- Run-out date = start date + supply length − 1 day. The last dose is taken the day before the supply is empty.
- Refill-by date = run-out date − 7 days, the standard buffer for ordering.
Worked example: a 30-tablet box of a medicine taken 1+0+1 (two doses a day) lasts 15 days. Starting on the 1st, the last dose falls on the 15th, and the reorder should happen by the 8th.
For the full system around refills — syncing them with doctor visits, longer supplies for chronic medicines — read the prescription refill guide.
Frequently asked questions
How do I calculate when my medicine will run out?
Divide the number of tablets or doses you have by the number you take per day. For example, 30 tablets taken 3 times a day lasts 10 days. This calculator does the arithmetic and gives you the exact run-out date and the day to reorder.
How early should I refill my prescription?
Seven days before the supply ends. That buffer covers pharmacy stock-outs, weekends and doctor delays without any missed doses.
Is my data from this calculator uploaded anywhere?
No. The calculation runs entirely in your browser. Nothing is stored or sent — close the tab and it is gone.