Fitness calculators for people who log every set

TDEE, macros, one rep max, plates, strength standards and body composition. Sixteen free tools that share your stats, so you type them once.

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315 lb

Each side: 45 + 45 + 45. Any weight, any gym →

All calculators

How the calculators fit together

Most fitness calculators ask for the same details again and again. FitForge keeps one profile (sex, age, height, bodyweight, activity and, if you know it, body fat) in your browser and every tool reads from it.

  1. Energy: the TDEE calculator sets your maintenance calories; the deficit calculator turns a goal weight into a daily target and a date.
  2. Nutrition: the macro calculator splits those calories into protein, carbs and fat, and an optional AI assistant turns the numbers into a sample day of meals.
  3. Strength: your one rep max drives percentage-based programming, the RPE chart and your strength level. The plate calculator tells you what to load.
  4. Body: a tape-measure body fat estimate feeds lean mass, FFMI and the more accurate Katch-McArdle metabolism formula.

Formulas are named on every page (Mifflin-St Jeor, Epley, the US Navy method, DOTS and others) with the sources behind them, so you can see exactly where a number comes from.

Quick answers

Are FitForge calculators free?

Yes. Every calculator is free with no sign-up. Results are calculated in your browser.

Does FitForge store my data?

Your stats are saved only in your own browser (localStorage) so you do not retype them on each calculator. You can clear them at any time on the privacy page.

Which calculator should I start with?

For nutrition, start with the TDEE calculator, then the macro calculator. For training, start with the one rep max calculator; its result feeds the plate calculator, RPE chart and strength standards.