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Refill it before it becomes a whole thing

This supply has likely run out

Based on these details, this supply may have already run out.

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Calculate when your medication will run out

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. Read more about how this calculator works.

It works for any repeat prescription — antidepressants, contraception, thyroid medication, blood pressure medication, HRT, asthma preventers, diabetes medication, and more. It also works for pet medication if your dog or cat is on a repeat script.

How the refill date calculator works

Step 01

Enter when you filled the script, how many were supplied, and your daily dose.

Step 02

The calculator estimates your run-out date and works backwards to find when to request a refill.

Step 03

Add a calendar reminder so you know exactly when to act — before it becomes urgent.

When should you request a refill?

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 "Adjust defaults".

If the suggested refill date has already passed, contact your pharmacy or doctor as soon as possible to avoid a gap in your medication.

Add a refill reminder to your calendar

After calculating your dates, use the "Add to Google Calendar" or "Add to other calendars" buttons to save a reminder. This works with Google Calendar, Apple Calendar, Outlook, and most other calendar apps. The event includes your estimated run-out date and refill request date.

Frequently asked questions

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?

Tick "I have some doses left already" and enter how many you have. 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.

Can I use this for pet medication?

Yes. It works for any repeat prescription including pet medication. Enter the dispense date, quantity, and daily dose exactly as you would for a human prescription.