Free Tools

Gym Calculators

No signup required. Use these tools to plan your training, nutrition, and track your progress.

Estimate your one-rep max from any submaximal set using 5 validated formulas with training percentages.

Calculate your total daily energy expenditure using Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.

Get your ideal protein, carb, and fat targets for fat loss, maintenance, or muscle gain.

Find your Basal Metabolic Rate — how many calories your body burns at complete rest using 3 validated formulas.

Calculate your daily calorie target for fat loss or muscle gain with projected timeline to your goal weight.

Get a composite 0-999 strength score from your bench, squat, deadlift, OHP, and row relative to bodyweight.

See exactly which plates to load on each side of the barbell with a color-coded visual breakdown.

Estimate your body fat percentage using the US Navy method with body composition breakdown and category classification.

Calculate your Body Mass Index with an animated gauge, healthy weight range, BMI Prime, and Ponderal Index.

Find your optimal daily protein target with per-meal breakdown based on bodyweight, activity level, and training goal.

Calculate your Fat-Free Mass Index with natural limit classification based on Kouri et al. (1995) research.

Calculate all three powerlifting bodyweight-normalized scores simultaneously from your total or individual lifts.

Find substitutes for any exercise from 873 movements, filtered by equipment type and grouped by category.

Get your next session prescription — add reps, increase weight, or deload — using RepStack's double progression engine.

RepStack calculates your e1RM, TDEE, and macros automatically with every set you log.