💪 Health & Fitness
Quick, formula-based fitness and nutrition calculators — work out your daily calories and macros, estimate body fat and ideal weight, plan protein and water intake, and gauge strength. Each uses an established formula and runs instantly in your browser. These are general estimates for information only, not medical advice.
BMR Calculator
Find your basal metabolic rate and daily calorie needs (TDEE).
Macro Calculator
Split your daily calories into protein, carbs and fat in grams.
One Rep Max Calculator
Estimate your one-rep max from a set, with training percentages.
Body Fat Calculator
Estimate body fat percentage with the U.S. Navy tape method.
Ideal Weight Calculator
Estimate ideal body weight from height with four classic formulas.
Protein Intake Calculator
Find your daily protein target in grams based on weight and goal.
Water Intake Calculator
Estimate how much water to drink each day from weight and activity.
Body Surface Area Calculator
Calculate body surface area with Mosteller, Du Bois and Haycock.
Guides & explainers
BMR vs TDEE: How Many Calories Should You Eat?
BMR and TDEE explained in plain English: what each means, how the Mifflin-St Jeor formula and activity multipliers work, and how to set calories to lose, gain or maintain weight.
GuideHow Much Protein Do You Need a Day?
How much protein to eat per day, by goal: the 0.8 g/kg RDA, 1.2–1.6 g/kg for active people, and 1.6–2.2 g/kg for building or preserving muscle — plus sources, timing and myths.