Free tools
Free fitness calculators
Free training calculators with no signup, no ads and no email capture. Every one runs entirely in your browser — nothing you type is uploaded — and every formula used is named and linked to its source so you can check the maths yourself.
Planning
Strength
Nutrition
Looking for muscle anatomy instead?
The interactive muscle map covers all 17 trainable muscle groups — anatomy, function, the best exercises for each, and how much weekly volume they need.
Common questions
- Are these fitness calculators free?
- Yes. Every tool here is completely free, with no account, no email capture and no paid tier. They are built and maintained by the team behind the Prept workout app.
- Do you store the data I enter?
- No. Every calculation runs entirely in your browser using JavaScript. Your weight, height, lifts and any other input never leave your device and are never sent to a server.
- Do these tools work on mobile?
- Yes, all of them are built mobile-first. The plate calculator in particular is designed to be used one-handed in a gym, and once the page has loaded it works without a connection.
- Can I share my results?
- Yes. Every tool encodes your inputs in the page URL, so copying the shareable link gives someone the exact same result you are looking at.