Body fat percentage, lean mass, FFMI, and muscle mass calculators. Browse our free body composition tools below — all calculators are instant, accurate, and require no sign-up.
Army Body Fat Calculator — Calculate your body fat percentage using the U.S. Army tape test method (AR 600-9). Determine if you meet military body composition standards.
BMI in Pregnancy Calculator — Calculate your pre-pregnancy BMI and track recommended weight gain by gestational week using IOM and ACOG guidelines for healthy pregnancy.
BMI Calculator for Kids — Calculate BMI for children ages 2–20 with CDC growth chart percentiles. Determine weight status using age-and-sex-specific pediatric standards.
BMI Calculator for Men — Calculate your BMI with male-specific interpretation, healthy weight range, estimated body fat, waist circumference risk, and calorie needs.
BMI Calculator for Teenagers — Calculate BMI for teenagers 13–19 with CDC age-and-sex-specific percentiles, weight status classification, and growth chart reference data.
BMI Weight Loss Goal Calculator — Set a target BMI and calculate exactly how much weight to lose, how long it will take, and the daily calorie deficit needed to reach your goal safely.
BMI Calculator for Women — Calculate BMI for women with female-specific body fat estimation, waist-to-hip ratio, cardiovascular risk assessment, healthy weight range, and calorie needs.
Body Adiposity Index (BAI) Calculator — Calculate your Body Adiposity Index to estimate body fat percentage without a scale. Uses hip circumference and height with the Bergman 2011 formula.
Body Density Calculator — Calculate body density from skinfold measurements and convert to body fat percentage using the Siri and Brozek equations. Free online tool.
Body Fat Calculator (Navy Method) — Free body fat percentage calculator using the U.S. Navy method. Estimate body fat from neck, waist, and hip circumference measurements — no special equipment needed.
Body Fat Calculator (3-Site Skinfold) — Estimate body fat percentage using the Jackson-Pollock 3-site skinfold method. Enter caliper measurements from three body sites for an accurate body composition estimate.
Body Fat Calculator (7-Site Skinfold) — Estimate body fat percentage with the Jackson-Pollock 7-site skinfold method. The most comprehensive caliper test using chest, midaxillary, triceps, subscapular, abdomen, suprailiac, and thigh.
Body Shape Calculator — Determine your body shape type — hourglass, pear, apple, rectangle, or inverted triangle — using bust, waist, and hip measurements with health risk analysis.
Body Water Percentage Calculator — Estimate total body water using the Watson formula. Calculate water percentage, intracellular and extracellular fluid volumes for hydration assessment.
Body Surface Area (BSA) Calculator — Calculate body surface area using six formulas — Du Bois, Mosteller, Haycock, Boyd, Gehan, Fujimoto — with comparison table and clinical dosing reference.
Height Estimation Calculator for Bedridden Patients — Estimate height for bedridden patients using knee height (Chumlea), arm span, ulna length (BAPEN), and demispan methods with technique guide and accuracy comparison.
FFMI Calculator — Fat-Free Mass Index — Calculate your Fat-Free Mass Index (FFMI) and normalized FFMI to assess muscularity relative to height. Scores above 25 are extremely rare for natural athletes. Includes classification table.
Gastric Sleeve Weight Loss Calculator — Project expected weight loss after vertical sleeve gastrectomy (VSG) by month — %EWL, %TWL, projected BMI, timeline, and comorbidity resolution rates.
Geriatric BMI Calculator — BMI calculator for adults 65+ with geriatric-specific ranges, obesity paradox context, mortality risk table, frailty screening, and protein/calorie targets for elderly.
Healthy Weight in Pregnancy Calculator — Track recommended pregnancy weight gain using IOM guidelines — weekly targets, calorie needs by trimester, gain status, safe exercise list, and weight component breakdown.
Lean Body Mass Calculator — Calculate your lean body mass using 3 validated formulas (Boer, Hume, James). Compare results to understand your fat-free weight including muscle, bone, and organs.
Maximum Muscular Potential Calculator — Estimate your maximum natural muscular potential using the Casey Butt, Martin Berkhan, and Lyle McDonald models. Find out how much muscle you can build without steroids.
Overweight & Obesity Risk Calculator — Comprehensive overweight assessment with BMI, waist circumference risk, healthy weight range, 5% and 10% weight loss benefits, disease risk table, and calorie deficit planning.
Relative Fat Mass (RFM) Calculator — Calculate your Relative Fat Mass from height and waist circumference. RFM estimates body fat percentage without a scale — 2018 Cedars-Sinai formula.
Skeletal Muscle Mass Calculator — Estimate your skeletal muscle mass using the Lee et al. prediction equation. Includes sex, age, height, weight, and ethnicity inputs with healthy SMM ranges.
Visceral Fat Estimate Calculator — Estimate your visceral fat level from waist circumference, age, and BMI. Understand your health risk with this free proxy for DEXA visceral fat scoring.
Weight Week-by-Week Planner — Plan your weight loss or gain with a week-by-week timeline showing adaptive calorie targets, BMI changes, milestones, and rate sustainability guidance.