About | When to Refill

Why this exists

At some point, everyone who takes regular medication has stood in their bathroom doing mental arithmetic at 10pm. How many left. How many days. Whether there's time. Whether the doctor can fit you in. Whether the pharmacy closes early on Wednesdays.

There is no good reason this calculation should live in your head. So we put it on the internet instead.

What it does and doesn't do

This is a date calculator. It takes a dispense date, a quantity, and a dose frequency, and works out when your supply will run out and when you need to act to avoid a gap.

It does not provide medical advice. It does not tell you what to take or when. It does not store your information, build a health profile, or encourage you to keep coming back. You use it, get your answer, and leave.

Who it's for

Anyone who takes repeat medication and wants to stay ahead of the paperwork. That includes people managing:

Antidepressants and mental health medication
Contraception and hormonal medication
Thyroid medication
Blood pressure and cardiovascular medication
HRT
Asthma preventers and inhalers
Diabetes medication
Any other repeat prescription

The tool is non-judgemental, plain-English, and designed to work in under 20 seconds — including for people who find prescription admin particularly hard to stay on top of.

How we built it

Private by default

Nothing you enter is stored or transmitted. Calculations happen in your browser.

No account needed

No sign-up, no email, no profile. Use it and close the tab.

Calm, not clinical

Designed to reduce stress, not add to it. No alarmist language, no medical jargon.

Single purpose

One job. No dashboard, no tracking, no upsell. Just the dates you need.

The photo upload feature

If reading a label is easier than typing, the upload option lets you photograph your medication bottle and have the details pre-filled. This uses AI to read the label — but you always confirm everything before a calculation runs. Nothing is stored.

Contact

If you have a question, spotted a bug, or want to get in touch, you can reach us at hello@whentorefill.com. We read everything but can't always reply individually.