Privacy

The numbers you type

Every calculator on this site runs in your browser. Your age, height, weight, measurements, heart rate and times are used inside the page to work out the result and are never sent to this site or to anyone else.

• Copy link puts your numbers in the link after the # sign. Browsers never send that part to a server; anyone you give the link to can see the numbers in it.
• Try this next links carry your age, sex, height, weight, units and (from the body fat calculator) body fat % the same way (after the #), so the next calculator is filled in.
• Save image and Share make the picture in your browser. Share hands it to your phone's own share menu; nothing passes through this site.

What your browser stores

• Only if you tick Remember my details on this device: your units, sex, age, height, weight and body fat % (if you entered one), in your browser's local storage under fmh-profile (and the choice itself under fmh-remember). Forget my details deletes both.
• If you mark guides as read in the Learn section, the list of those guides is kept in your browser's local storage too, so we can show your progress. Use "Reset progress" on the Learn page, or clear your browser data, to delete it.
• Your light or dark theme choice, under fmh-theme.
• Offline copies for the app: on the live site, a service worker keeps copies of the pages you've opened (and, if you press the button on the app page, all calculators), so they work without a connection. They contain no personal data and are removed when you clear this site's data or uninstall the app.
• Fonts are served from this site itself, so no font service learns that you visited.
• No accounts and no sign-up. The site itself sets no cookies.

Usage counts

To see which calculators are useful, the site adds up anonymous daily totals: how many times each calculator was used, how often Copy link, Save image and Share were pressed, and which calculator a "Try this next" link was followed from and to. Only the day, the calculator(s), the page language and the total are stored. Never the numbers you typed, nothing about you, no cookies and no identifiers.

The contact form

The form asks for no name, e-mail address or account. What is stored, in a database on Cloudflare: the message type, your message, the page you picked (optional), your rating (optional), the date, and the country Cloudflare detects from your connection. Your IP address is not stored.

• If you write in another language, the message is translated into English with Cloudflare Workers AI so it can be read. The original is kept next to the translation.
• To stop spam, the form uses Cloudflare Turnstile, a security check that runs in your browser and is sent to Cloudflare. It doesn't use your message.
• Messages are only read by the site owner, never shared or sold, and deleted automatically after 12 months. Please don't put health details in a message.

Visitor statistics

The site uses Cloudflare Web Analytics to count page views. It sets no cookies, doesn't track you across sites and doesn't identify you.

Advertising

No ads are shown yet. If Google AdSense ads are added later, this section will describe them before they appear, and visitors in the EEA, the UK and Switzerland will be asked for consent first.

Hosting

The site is hosted on Cloudflare, which processes basic technical data such as IP addresses to deliver pages and protect against attacks. This covers loading the pages, not the numbers you type into them.

Your rights

Under the GDPR you can ask what data is held about you, and ask for it to be corrected or deleted. Because contact messages carry no name or e-mail, the way to have one deleted is to send a new message through the contact form quoting its date and first words.

Changes

If the site starts handling any other personal data, this page will be updated first and will list exactly what changes.