About FitCalcs

FitCalcs is an independent website that provides free fitness and nutrition calculators. The goal is simple: give you clear, accurate answers to everyday training and diet questions — how many calories you need, how much protein to eat, how fast you ran, how much you could lift — without accounts, paywalls, or clutter. Every tool works instantly in your browser and is free to use.

Who we are

FitCalcs is built and maintained by Jesse, a software developer who reviews fitness and nutrition research as a personal interest. Jesse is not a doctor or registered dietitian — and is careful to say so. The calculators implement well-established, peer-reviewed formulas and present them in a fast, easy-to-use interface. Every result comes with the formula, its source, and an honest description of its limitations, so you can take the numbers to a professional or check the method yourself.

This is a small, independent project — not a large publisher or medical organization. Because we cannot examine your individual circumstances, we focus on transparency: every calculator shows the exact formula it uses, defines each variable, and cites the original published source.

How the numbers are calculated

Our calculators use recognized, published formulas rather than numbers we invented. Calorie needs are based on the Mifflin-St Jeor equation combined with standard activity multipliers; body-fat estimates use the U.S. Navy circumference method; strength estimates average several established rep-max formulas. These are estimates to guide you, not exact prescriptions — real results vary from person to person, and you should adjust based on how your body responds.

For the full detail on where each formula comes from, how we handle its limitations, and when we last reviewed it, see our methodology and editorial standards.

Not medical advice

FitCalcs is for general educational use by healthy adults. It is not a substitute for professional medical or dietary advice. If you have a medical condition, a history of disordered eating, or are pregnant, please consult a qualified professional before making changes to your diet or exercise.

Corrections and contact

We take accuracy seriously. If you spot a formula that looks wrong, a result that does not add up, or a source that needs updating, please tell us and we will investigate and correct it. Email hello@fitcalcs.app or use the contact page.