Fitness & Body Composition Calculators
Measure and track your body composition with evidence-based calculators for BMI, body fat percentage, ideal weight, and more. Based on formulas validated against DEXA and clinical measurements.
20 free tools
Army Body Fat Calculator
Estimate your body fat percentage using the U.S. Army tape test method. Based on gender, age, height, neck, and waist measurements.
Calculate Body Fat →
FFMI Calculator
Calculate your Fat-Free Mass Index and normalized FFMI. See how your muscularity compares to the natural genetic limit.
Calculate FFMI →
VO2 Max Calculator
Estimate your VO2 max with 6 validated methods: Cooper run, walking test, step test, or no-exercise estimate. See fitness classification by age.
Calculate VO2 Max →
One Rep Max (1RM) Calculator
Estimate your one rep max using 7 proven formulas. Full training load table for bench press, squat, deadlift, and more.
Calculate 1RM →
Training Volume Calculator
Get personalized weekly set recommendations per muscle group based on your experience, goals, age, sleep, and recovery. With suggested workout splits.
Get My Volume →
Bulking Calorie Calculator
Calculate your ideal calorie surplus for lean muscle gain. Get bulking calories, macro breakdown, and weekly weight gain estimate.
Calculate Surplus →
Creatine Dosage Calculator
Calculate your optimal creatine dose based on body weight. ISSN-backed loading and maintenance protocols with teaspoon conversions.
Calculate Dose →
Ideal Body Weight Calculator
Calculate your ideal body weight range based on height, gender, and frame size using multiple evidence-based formulas.
Calculate Weight →
Creatine Hydration Calculator
Calculate optimal water intake when using creatine supplements.
Calculate Hydration →
BMI Calculator
Calculate your Body Mass Index and see your weight category based on WHO guidelines. Includes healthy weight range for your height.
Calculate BMI →
Calories Burned Calculator
Calculate calories burned during exercise and daily activities using MET values from the Compendium of Physical Activities for 30+ exercises.
Calculate Calories Burned →
Body Fat Calculator
Calculate your body fat percentage using the U.S. Navy method. Simple neck, waist, and hip measurements give accurate body composition estimates.
Calculate Body Fat →
Body Roundness Index (BRI)
Calculate your Body Roundness Index using waist circumference and height. BRI measures central adiposity and predicts health risk more accurately than BMI.
Calculate BRI →
Metabolic Age Calculator
Calculate your metabolic age by comparing your BMR to population averages. Find out if your metabolism is younger or older than your actual age.
Calculate Metabolic Age →
Zone 2 Heart Rate Calculator
Calculate your Zone 2 heart rate training range for aerobic base building, fat burning, and mitochondrial health. Supports % Max HR, Karvonen, and Maffetone methods.
Calculate Zone 2 →
Running Calorie Calculator
Calculate calories burned running by distance, pace, and terrain. Covers 5K through marathon with MET-based formula from the Compendium of Physical Activities.
Calculate Running Calories →
Running Pace Calculator
Calculate your running pace per mile or per km, predict finish time from pace, or estimate distance covered. Includes mile-by-mile splits and race time equivalents for 5K, 10K, half marathon, and marathon.
Calculate Pace →
Steps to Calories Calculator
Convert any step count to calories burned using your weight, stride length, and walking pace. Works with any fitness tracker. Includes steps-to-calories chart for 1,000–20,000 steps.
Calculate Calories →
Treadmill Calorie Calculator
Calculate calories burned on a treadmill by speed, incline, duration, and body weight. Uses the ACSM metabolic equation — the gold standard for treadmill calorie estimation. Includes incline comparison table.
Calculate Calories →
Cycling Calorie Calculator
Calculate calories burned cycling by intensity, duration, and body weight. Covers road cycling at every speed, mountain biking, and stationary bike. Uses the 2011 Compendium of Physical Activities MET values.
Calculate Calories →
Beyond the Scale: Measuring What Matters
Bodyweight alone tells an incomplete story. Two people at the same weight can have vastly different body compositions — and very different health risk profiles. These calculators help you understand what your body is made of, not just how much it weighs.
Which Calculator Should You Start With?
- BMI Calculator — Quick screening tool using just height and weight. Good starting point but has known limitations for athletes and muscular individuals
- Body Fat Calculator — Uses the U.S. Navy circumference method for a more accurate picture of body composition. Requires a tape measure
- Body Roundness Index — Newer metric that captures central adiposity (belly fat) specifically, which is the strongest predictor of metabolic disease risk
- Ideal Body Weight — Compares multiple evidence-based formulas (Devine, Robinson, Miller, Hamwi) to give you a realistic target range
Tracking Progress Over Time
Body composition changes slowly. Measure under consistent conditions (same time of day, same hydration state) and track trends over weeks, not daily fluctuations. A 1-2% change in body fat percentage per month is excellent progress.