Fitness Calculators — BMI, BMR, Calories, Macros, Pace & 1RM
One workspace for everyday fitness math. Change the shared inputs, then switch between body composition, energy, nutrition, running and strength tools without opening a new calculator page.
BMI Calculator
Calculate body mass index from height and weight and keep the result alongside the rest of your fitness numbers.
BMI = weight ÷ height²Adult BMI reference bands are shown as context; BMI is a screening measure and does not directly measure body composition.
BMR + TDEE Calculator
Estimate resting energy expenditure with Mifflin–St Jeor, then scale it by activity to get a planning estimate for daily energy needs.
BMR → TDEE = BMR × activity factorBelow estimated maintenance · -233 kcal/day difference.
Body Fat Calculator
Estimate body-fat percentage with the U.S. Navy circumference method. Measurement technique can materially affect the estimate.
U.S. Navy circumference equationsMacro Calculator
Turn a calorie target into a simple protein, fat and carbohydrate split. The defaults are a planning heuristic, not a prescribed diet.
Protein × 4 + carbs × 4 + fat × 9 ≈ caloriesCalculated from the current calorie target using the lab's protein and fat assumptions; carbohydrate calories fill the remainder.
Running Pace Calculator
Convert a distance and elapsed time into pace, speed, and simple race-time projections.
Pace = elapsed time ÷ distanceOne-Rep Max Calculator
Estimate one-repetition maximum from a submaximal set using the Epley equation.
1RM = weight × (1 + reps ÷ 30)