Free Tools
Gym Calculators
No signup required. Use these tools to plan your training, nutrition, and track your progress.
1RM Calculator
Estimate your one-rep max from any submaximal set using 5 validated formulas with training percentages.
TDEE Calculator
Calculate your total daily energy expenditure using Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.
Macro Calculator
Get your ideal protein, carb, and fat targets for fat loss, maintenance, or muscle gain.
BMR Calculator
Find your Basal Metabolic Rate — how many calories your body burns at complete rest using 3 validated formulas.
Calorie Deficit / Surplus
Calculate your daily calorie target for fat loss or muscle gain with projected timeline to your goal weight.
Strength Standards
Get a composite 0-999 strength score from your bench, squat, deadlift, OHP, and row relative to bodyweight.
Plate Calculator
See exactly which plates to load on each side of the barbell with a color-coded visual breakdown.
Body Fat Calculator
Estimate your body fat percentage using the US Navy method with body composition breakdown and category classification.
BMI Calculator
Calculate your Body Mass Index with an animated gauge, healthy weight range, BMI Prime, and Ponderal Index.
Protein Calculator
Find your optimal daily protein target with per-meal breakdown based on bodyweight, activity level, and training goal.
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RepStack calculates your e1RM, TDEE, and macros automatically with every set you log.