About FitCalc
Free fitness tools, built on the evidence
FitCalc started with a simple frustration: the best fitness calculators on the web were buried under sign-up walls, paywalls, and pop-ups — and half of them used formulas you couldn't verify. We wanted a single, fast, free toolkit that respects your time and your privacy.
What we do
We build calculators and guides for everyday training and nutrition — BMI, body fat, BMR, TDEE, calories and macros, protein needs, water intake, one-rep max, plate loading, heart-rate zones, pace, progress tracking and workout planning. Every tool runs instantly in your browser, with no account required and nothing to install.
How we build our tools
Our calculators use established, peer-reviewed formulas rather than black-box guesses, so you can check our work:
- BMR & calories — Mifflin–St Jeor equation, with the Katch–McArdle option when body-fat percentage is known.
- TDEE — BMR scaled by standard activity multipliers.
- One-rep max — Epley and Brzycki formulas.
- Heart-rate zones — the Karvonen (heart-rate reserve) method.
- Protein & macros — ranges drawn from current sports-nutrition research (typically 1.6–2.2 g/kg for active individuals).
Because these are population-level formulas, results are estimates — useful starting points, not exact prescriptions. We say so clearly wherever it matters.
Our editorial approach
Our supplement and nutrition guides aim to be genuinely evidence-based. We lead with mechanisms and dosages backed by research, we flag where the evidence is weak, and we're candid when a popular product simply isn't worth it. When we recommend a brand, the ranking is based on ingredient quality, transparency and third-party testing — never on what pays us the most.
How we stay free
FitCalc is funded by advertising and by affiliate commissions on some of the products we recommend. This lets us keep every tool free and sign-up-free. It never changes our recommendations — see our affiliate disclosure and privacy policy for the details.
Get in touch
Spotted an error, or want us to build a tool? We'd love to hear from you — head to our Contact page.