FitMathHub is a set of free fitness and sleep calculators that show their working. It's run by one independent developer in the EU who also builds a few other free tool sites. No name and no photo, on purpose: the site is about the math, and the math is checkable.
Why it exists
Calorie, BMI, heart-rate and sleep calculators are everywhere, but most of them hide the formula. Two sites can give two different answers for the same person and neither says why. This site shows the published equation behind every number, your own numbers plugged into it, and where the equation comes from.
Who writes the pages
The site's owner is a developer, not a doctor, dietitian or coach. That's why the pages stick to what published formulas and reference values say, link to the papers and official pages they come from, and never give personal advice.
How the calculators are made
- Every formula comes from a published source: a peer-reviewed paper, an official report (FAO, EFSA, the US National Academies, the U.S. Navy) or a position stand. The sources are linked under each calculator with the date they were last checked. How we calculate lists them all.
- The calculators and their first-draft texts are built with AI help. Every number on a page is checked against its source, and every worked example is checked by automated tests against the calculator itself.
- Where sources disagree or a formula has known limits, the page says so.
- If a result or a sentence looks wrong, say so and it gets checked and fixed.
- The full rules are in the editorial and corrections policy.
How the site pays for itself
The calculators are free and stay free. The site may show a small number of ads, clearly labeled "Advertisement" and never placed between the fields and the result. Your numbers are never passed to them: they stay in the page on your device.
What this site will never do
- Give diet plans, weight-loss targets, medical advice or diagnoses.
- Send the numbers you type to a server, or ask you to sign up.
- Rank people by weight, BMI or body fat, or invent statistics.