Body Metrics & Weight Calculators

33 professional health calculators • 100% free to use

Calculate BMI, body fat percentage, ideal weight, and weight loss timeline. Track body composition, muscle mass, BSA, and obesity risk with free tools.

All Body Metrics & Weight Calculators

ABSI Calculator

Free ABSI calculator computes A Body Shape Index from waist, height, and BMI to estimate visceral fat and mortality risk independent of body mass index.

Adult BMI Calculator for Men & Women

Use the adult BMI calculator to find your BMI with WHO categories. Enter metric or imperial units to see your status and BMI ranges quickly and clearly.

Army Body Fat Calculator

Check compliance with the Army body fat calculator per AR 600-9 standards. Enter circumference measures by sex to estimate body fat % and see pass/fail status.

Body Adiposity Index Calculator (BAI)

Free body adiposity index calculator estimates body fat percentage from hip circumference and height using the BAI formula, no weight or scale needed.

Body Composition Calculator

Use our body composition calculator to estimate body fat percentage, fat mass, and lean mass from tape measurements. Switch units and get clear categories.

Body Fat Calculator

Estimate with the body fat percentage calculator (body fat calculator) using Navy circumference equations. Supports metric/imperial and sex‑specific inputs.

Body Measurement Calculator

Use our body measurement calculator to capture wrist, waist, hip, and height. View WHR, WHtR, and a wrist-based frame size hint with metric/US units and labels.

Body Roundness Index Calculator (BRI)

Estimate adiposity from height and waist with our body roundness index calculator. Get your BRI value and interpretive ranges for clear health risk context.

Body Shape Calculator & Guide Based on Measurements

Discover your proportions with our body shape calculator. Enter bust, waist, and hip measurements to classify your shape and get style and fitness tips.

Body Type Calculator

Use our body type calculator to identify ectomorph, mesomorph, or endomorph tendencies. Get practical training and nutrition guidance for your somatotype.

BSA Calculator

Free BSA calculator with Mosteller, Du Bois, and Haycock formulas. Calculate body surface area in m² for chemotherapy dosing and medication protocols.

Child BMI Calculator

Free CDC child BMI calculator for ages 2-20. Enter height, weight, age, and sex to get BMI percentile, z-score, weight category, and healthy range instantly.

Conicity Index Calculator

Free conicity index calculator measures central obesity from waist, weight, and height, scoring how cylindrical your body shape is for cardiovascular risk.

FFMI Calculator

Calculate muscularity with the FFMI calculator. Input body weight, height, and body fat % to compute FFMI, then compare with sex-specific reference ranges.

Frame Size Calculator

Frame size calculator to classify your build as small, medium, or large using wrist circumference and height — fast results and helpful weight context today.

Healthy Weight Range Calculator

Find your healthy weight range by height with our healthy weight range calculator. See BMI 18.5–24.9 targets, midpoint goal, and metric/US unit support.

Ideal Body Weight Calculator

Find your IBW with the ideal body weight calculator (IBW calculator) using Devine, Robinson, Hamwi, and Miller formulas. Adjust for height, sex, and frame size.

Lean Body Mass Calculator (LBM)

Use the lean body mass calculator to estimate fat‑free mass (LBM) with Boer, James, Hume, and Janma formulas. Compare results, switch units, and see LMI.

Muscle Mass Calculator

Calculate skeletal muscle mass with our free muscle mass calculator. Enter weight and body fat % to see SMM, lean mass, fat mass, SMI, and body composition.

Navy Body Fat Calculator

Use our Navy body fat calculator to estimate body fat with the official U.S. Navy tape test. Enter neck, waist, height, and hips (women). See age limits.

Obesity Calculator

Free obesity calculator shows your BMI obesity class (1, 2, or 3) using WHO cutoffs. See weight ranges, body fat estimate, and a plan to reach a healthy BMI.

Overweight Calculator

Use our overweight calculator to check BMI using WHO cutoffs. Enter height and weight in metric or US units to see category, health context, and target range.

Ponderal Index Calculator

Free ponderal index calculator computes weight in kg divided by height cubed, a height-stable leanness measure for tall, short, and newborn bodies alike.

Relative Fat Mass Calculator (RFM)

Free relative fat mass calculator estimates body fat percentage from height and waist with the validated RFM formula, a simpler, more accurate BMI alternative.

Reverse BMI Calculator

Free reverse BMI calculator to find the exact weight for any target BMI and height. Set BMI goals, compare thresholds, and plan your path to a healthy weight.

Skeletal Muscle Mass Percentage Calculator by Age and Sex

Free skeletal muscle mass percentage calculator to check your SMM against healthy ranges by age and sex. Interpret InBody, DEXA, or smart scale results.

Waist to Height Ratio Calculator (WHtR)

Use our waist to height ratio calculator (WHtR) to screen adiposity risk. Enter height and waist in metric or US to see WHtR, risk band, and waist target.

Waist to Hip Ratio Calculator (WHR) for Health Risk

Calculate WHR with our waist to hip ratio calculator. Enter waist and hip measurements to see category and cardiometabolic risk ranges for men and women.

Weight Gain Calculator for Bulking and Muscle Building

Use our weight gain calculator to set a safe calorie surplus, estimate daily calories and macros, and plan a realistic timeline to gain weight steadily.

Weight Loss Calorie Calculator

Free weight loss calorie calculator to find your calorie deficit for weight loss. Estimates BMR, TDEE, target intake, macros, and a timeline to your goal.

Weight Loss Calculator by Date

Free weight loss calculator by date with timeline milestones. Set a goal weight and pace or target date to see your finish date, deficit and BMI change.

Weight Loss Percentage Calculator

Free weight loss percentage calculator. Enter your starting and current weight to see percent lost, total change in kg/lb, weekly pace, and goal timeline.

Wrist Size Calculator

Free wrist size calculator to find your body frame size from wrist circumference and height. Get instant small, medium, or large frame classification.

Total Tools

33

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Results

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Why Use Our Body Metrics & Weight Calculators?

Our body metrics and weight calculator collection includes 33 specialized tools that help you measure BMI, body fat percentage, ideal body weight, body surface area (BSA), and weight loss timelines. Each calculator uses clinically validated formulas — including the Mifflin-St Jeor equation, Devine formula, and CDC BMI classifications — to deliver accurate results you can discuss with your healthcare provider.

Who Are These Calculators For?

These tools are designed for anyone tracking body composition changes, planning weight loss goals, or monitoring fitness progress. Healthcare professionals use our BMI and BSA calculators for clinical assessments, while fitness enthusiasts rely on body fat and muscle mass calculators for training insights.

How Our Calculators Work

Enter your measurements — height, weight, age, and gender — and get instant results with clinical interpretations. All calculations happen in your browser using peer-reviewed formulas. No data is stored or transmitted, ensuring complete privacy.

Key Benefits

  • Medical-grade accuracy based on WHO and CDC guidelines
  • Instant results with detailed explanations and recommendations
  • 100% private — all calculations run locally in your browser
  • No registration, no personal data collected

Frequently Asked Questions

How accurate are online BMI and body fat calculators?

Our BMI calculator uses the standard WHO formula (weight in kg divided by height in meters squared) which is the same formula used in clinical settings. Body fat calculators use the U.S. Navy method or skinfold equations, which provide estimates within 3-4% of DEXA scan results for most people.

What is a healthy BMI range for adults?

According to the WHO, a healthy BMI for adults is between 18.5 and 24.9. A BMI below 18.5 is classified as underweight, 25-29.9 as overweight, and 30 or above as obese. However, BMI does not account for muscle mass, bone density, or fat distribution.

How do I calculate my ideal body weight?

Our ideal body weight calculator uses several validated formulas including the Devine, Robinson, Miller, and Hamwi equations. Each formula considers your height and gender to estimate a healthy weight range. The calculator shows results from all formulas so you can see the range.

Can I use these calculators to plan a weight loss timeline?

Yes. Our weight loss date calculator lets you set a target weight and see a realistic timeline based on your calorie deficit. It factors in your current weight, activity level, and goal to estimate when you can reach your target safely (1-2 lbs per week is recommended).

What is body surface area (BSA) and why does it matter?

Body surface area estimates the total surface of your body in square meters. It is commonly used in medicine for calculating drug dosages (especially chemotherapy), determining cardiac output, and assessing burn severity. Our BSA calculator uses the Mosteller and DuBois formulas.

Explore More Health Calculators

Discover our complete collection of 304 health calculators across 9 categories