The short version
Every calculator on this site is JavaScript running in your browser. Your weight, your reps, your bedtime and your measurements are never transmitted anywhere — there is no server to send them to. What you type stays on your device.
What is stored on your device
- Your theme choice. If you switch between light and dark, that preference is saved in your browser's local storage so the page does not flash the wrong colour next time. It is one word, it never leaves your browser, and clearing site data removes it.
- Your inputs, in the address bar. Changing a field updates the query string so you can copy the URL and share the exact result. That URL is only shared if you share it.
Advertising
This site is funded by display advertising. Advertising partners may set cookies or read device identifiers to measure and, where you have consented, personalise the ads you see. That is their processing, under their own policies, not ours.
Where the law requires a certified consent mechanism — the EEA, the UK and Switzerland — this site does not currently operate one, so no advertising is requested at all for visitors we detect as being in those regions. No ad is served, no advertising cookie is set, and no request is made to an advertising network. The calculators are unaffected and work identically; the reserved ad space simply stays empty. Region is inferred from your browser's own time-zone setting, which never leaves your device, and the test is deliberately over-inclusive. If that changes — if a Google-certified consent management platform is added — this page will be updated before it does, and a consent notice will appear at that point.
Google, as one of these partners, uses cookies to serve ads based on prior visits to this or other sites. You can opt out of personalised Google advertising at Google's ad settings, and manage third-party cookie use for personalised advertising at aboutads.info/choices or youronlinechoices.eu.
Analytics
Aggregate traffic measurement — page views, referrers, broad country and device type — is used to see which pages are worth improving. It is not linked to a name, an email address or anything you typed into a calculator.
Server logs
The host records standard request logs, including IP addresses, for security and abuse prevention. These are retained briefly and are not combined with anything else on this page.
Children
This site is not directed at children under 13 and does not knowingly collect information from them.
Your rights
Depending on where you live you may have the right to access, correct or delete personal data held about you, and to object to processing. Given how little this site holds, most such requests concern advertising cookies, which you can also clear yourself in your browser. Write to the address on the contact page and we will respond.
Changes
If this policy changes, the date at the top of the page changes with it.