Enter your script details. Get the dates you actually need, in seconds.
This calculator estimates how long your medication supply will last based on the date, quantity, and dose you enter. It then shows when to request a refill, and when to book an appointment if you need a new script.
Enter when you filled the script, how many were supplied, and your daily dose.
The calculator estimates your run-out date and works backwards to find when to request a refill.
Add a calendar reminder so you know exactly when to act — before it becomes urgent.
A good rule of thumb is to request your refill 7–14 days before you run out. If you need a doctor appointment to get a new script, add extra time for the appointment wait. The calculator includes a 7-day buffer by default, which you can adjust under "Make this more accurate".
If the suggested refill date has already passed, contact your pharmacy or doctor as soon as possible to avoid a gap in your medication.
After calculating your dates, use the "Refill reminder" button to download a calendar event (.ics). This works with Apple Calendar, Google Calendar, Outlook, and most other calendar apps. The event includes your estimated run-out date and refill request date.
Can this calculator tell me when to take my medication?
No. It only estimates refill timing based on the details you enter. Always follow the instructions from your doctor or pharmacist.
How do I calculate when my medication will run out?
Enter the date you started or filled the script, the quantity supplied, and how many doses you take per day. The calculator estimates your run-out date from those details.
What if I have some tablets left already?
Use the "Make this more accurate" section and enter your doses remaining. The calculator will estimate your run-out date from today instead of the original dispense date.
What if my dose changes?
Recalculate using your current dosage instructions. Do not rely on an old calculation if your dose has changed.
Does this replace advice from my doctor or pharmacist?
No. This tool is only a date calculator. It does not provide medical advice, dosage advice, or prescription instructions.
Does this store my medication information?
No. The calculator does not store medication details, uploaded images, or results. Nothing is saved when you close the page.