Evidence-based formulas · 100% private
Know your numbers. Train smarter.
Free health and fitness calculators built on peer-reviewed equations — with clear guides so you understand every result.
Calculators
Calorie & TDEE
BMR, TDEE and targets for fat loss, maintenance or muscle gain.
OpenBMI & Body Fat
BMI category plus U.S. Navy body fat percentage estimate.
OpenMacro Split
Protein, carbs and fat in grams for Balanced, Keto or High Protein.
OpenWater Intake
Daily hydration in liters and glasses with a built-in tracker.
OpenScientific formulas
Mifflin-St Jeor, U.S. Navy and established hydration guidelines.
Instant results
Everything updates live as you move the sliders — no sign-up.
Private by design
All calculations run in your browser. We never store your inputs.
Latest guides
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Your Total Daily Energy Expenditure is the foundation of every effective nutrition plan. Here's how to use it without crash dieting.
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A science-backed look at protein targets, timing, and food sources for lifters at every level.
WorkoutsA Beginner's 3-Day Full-Body Workout Routine
Build strength and confidence with a simple, effective routine you can complete in under an hour.