Free Fitness Calculators for Strength, Nutrition & Body Composition
25 free tools. No sign-up. Formulas cited.
1RM Calculator Estimate your one-rep max from any weight and rep count. Bench Press Max Calculator Estimate your max bench press from weight and reps. Squat Max Calculator Estimate your max squat from weight and reps. Deadlift Max Calculator Estimate your max deadlift from weight and reps. Overhead Press Max Calculator Estimate your strict press or military press max from weight and reps. Rep Max Calculator Convert a known weight and reps to any target rep count. 1RM Percentage Calculator Find your weight at any training percentage, or reverse-calculate your 1RM. Strength Standards Calculator Compare your bench, squat, deadlift, or OHP 1RM with bodyweight-based reference standards.
Training Max Calculator Convert your 1RM into a safe training max for 5/3/1 programs. 5/3/1 Calculator Generate the full Wendler 5/3/1 four-week cycle from your training max. Warm-Up Set Calculator Generate your full warm-up ramp from the empty bar to your working weight. RPE & RIR Calculator Convert a completed set into your estimated 1RM using the RTS RPE chart.
TDEE Calculator Find your daily maintenance calories using the Mifflin-St Jeor equation. BMR Calculator Find your Basal Metabolic Rate using Mifflin-St Jeor or Harris-Benedict. Macro Calculator Convert your daily calories into protein, carb, and fat targets. Protein Intake Calculator Find your daily protein range based on ISSN sports nutrition guidelines. Water Intake Calculator Find your daily water target based on body weight and activity level. Calorie Deficit Calculator Calculate your daily calorie deficit, weight-loss target, and estimated timeline. Body Fat Calculator Estimate your body fat percentage using the US Navy tape-measure method. BMI Calculator Calculate your BMI and see your adult BMI category and BMI-based weight range. Lean Body Mass Calculator Calculate lean body mass from body fat percentage or estimate it with the Boer, James, or Hume formula. FFMI Calculator Calculate your fat-free mass index, normalized FFMI, and lean mass from body composition. Ideal Weight Calculator Compare Devine, Robinson, Miller, and Hamwi ideal body weight estimates with a BMI-based healthy weight range. Calories Burned Calculator Estimate calories burned from walking, running, lifting, cycling, cardio, and other activities using MET values.
About RepMaths
RepMaths is a free collection of fitness calculators covering strength, training, nutrition and body composition — each built on established, cited formulas such as Mifflin-St Jeor for BMR and TDEE, the US Navy body-fat method, Epley and Brzycki for one-rep max, the Reactive Training Systems RPE scale, and ISSN protein guidelines.
- ✓ Formulas and sources cited on every page
- ✓ No sign-up required
- ✓ Works in lb and kg
Built by a lifter. Read the RepMaths story →