Free tools
Fitness calculators & tools
Evidence-based calculators that show their work. Every formula used is documented on each tool's page — no black-box math, no email required, no paywall.
Macro Calculator
Your TDEE, daily calorie target, and protein / carb / fat grams for cutting, maintenance, or bulking.
- Inputs
- Sex, age, height, weight, activity, goal · body fat % optional
- Formulas
- Mifflin-St Jeor · Katch-McArdle
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1RM Calculator
Estimate your one-rep max from any rep set, plus a full training load table from 67% to 100%.
- Inputs
- Weight lifted, reps completed · exercise optional
- Formulas
- Epley · Brzycki · Lombardi · O'Conner
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Plate Calculator
Target weight in, plate stack per side out. Visual bar diagram and custom plate sets for your gym.
- Inputs
- Target weight, bar weight · available plates optional
- Formulas
- Greedy plate selection · lb/kg conversion
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Body Fat Calculator
Estimate body fat percentage with a tape measure — no calipers needed. Includes category classification and lean mass.
- Inputs
- Sex, height, neck, waist · hip (women) · weight optional
- Formulas
- US Navy circumference method
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