About FitnessCalculator.net

FitnessCalculator.net is a collection of seventeen focused fitness and health calculators — BMI, calories, TDEE, BMR, body fat, ideal weight, macros, net carbs, protein, water, running pace, heart-rate zones, zone 2, one-rep max, sleep cycles, pregnancy due dates, and ovulation timing — 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 or a clearly labeled convention — WHO BMI categories, the Mifflin-St Jeor equation, the US Navy circumference method, the classic ideal-weight formulas, standard activity multipliers, the Karvonen heart-rate formula, Naegele's rule, and the net-carb, sleep-cycle, and calendar-method ovulation conventions — and each page names the formula or convention it uses, states its limitations, 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 published population formulas. They cannot account for your individual health context and must not be used to diagnose or treat any condition — 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.