About FitnessCalculator.net

FitnessCalculator.net is a collection of focused fitness and health calculators — BMI, calories, BMR, body fat, ideal weight, macros, running pace, and heart-rate zones — that run entirely in your browser. It is published by Sumvia, the team behind the Sumvia.net calculator network.

Published formulas, stated openly

Every calculator here implements a recognized published method — WHO BMI categories, the Mifflin-St Jeor equation, the US Navy circumference method, the classic ideal-weight formulas, standard activity multipliers, and the Karvonen heart-rate formula — and each page names the formula it uses and shows the arithmetic. You should never have to wonder where a number came from.

Browser-native, no accounts

Nothing you enter — height, weight, measurements, ages — is transmitted, logged, or stored. All calculation happens on your device, there is no registration, and the tools stay usable on a flaky connection once the page has loaded. This is a deliberate design constraint of every Sumvia site.

Tested calculation logic

Each formula is implemented as small, typed functions with automated tests checked against hand-computed values, and the worked examples in page copy are generated by the same code that powers the calculators — so the documentation cannot drift from the implementation. See the methodology and accuracy page for the full approach.

Not medical advice

These calculators provide general educational estimates from population-level formulas. They cannot account for your individual health context and are not a substitute for professional advice. Consult a qualified healthcare professional before making decisions about diet, exercise, or health — especially with any medical condition.

Get in touch

Found a problem, or want to suggest a calculator? See the contact page — reports of suspected calculation issues are especially welcome and are treated seriously.