Free tools

Fitness calculators you can trust.

Fast, accurate, no sign-up. Built on the same formulas that power Prime Progression.

BMI Calculator

Body Mass Index — a quick screening metric for weight categories relative to height.

Basal Metabolic Rate — the calories your body burns at complete rest.

Total Daily Energy Expenditure — your real-world calorie needs including activity.

Fat-Free Mass Index — how muscular you are relative to your height. Better than BMI for lifters.

Estimate your one-rep max from any weight × reps combination. Compares three formulas.