Body Composition Calculators
Calculate BMI prime, body fat and body surface area and other body composition calculations.
Weight alone says little about health. These calculators estimate what that weight is made of, where it is carried, and what range is typical for your height — each with a different published method, and each with blind spots the others help fill.
Which Body Composition calculator do you need?
- What weight range is typical for my height?Healthy Weight CalculatorThe weight range that corresponds to the WHO normal BMI band for your height.
- How much of my weight is fat?Body Fat CalculatorThe U.S. Navy tape-measure method, from height, neck and waist (and hip for women).
- Where do I carry weight?Waist-to-Height Ratio CalculatorWaist relative to height — a measure of central fat that BMI cannot show.
- How much of me is not fat?Lean Body Mass CalculatorLean mass from weight, height and sex using the Boer formula.
- How do my body fat numbers compare with reference ranges?Ideal Body Fat CalculatorPlaces a body-fat percentage into the ACE reference categories by sex.
All Body Composition Calculators
Use more than one measure
BMI and healthy-weight ranges compare weight with height only, so a muscular person and a sedentary person of the same size get the same answer. A tape-measure body-fat estimate and a waist measure add the two things BMI misses — composition and where fat sits — and are worth checking together.
Limitations
- Formula-based estimates, not a body-composition scan; results are screening information, not a diagnosis.
- Methods were developed on adult populations and are less reliable for children, athletes and during pregnancy.
Body Composition Guides
BMI vs Body Fat Percentage: Which Is a Better Health Indicator?
BMI is a quick screening tool based only on height and weight — it can't tell muscle from fat, so a muscular, athletic person can register as "overweight" or "obese" despite having very little body fat. Body fat percentage measures composition directly and is the more accurate indicator for an individual, but BMI remains useful as a fast, no-measurement population-level screen.
Read guideBody Type Calculator: How the Height-to-Wrist Ratio Sorts Ectomorph, Mesomorph, Endomorph
Worked examples running the Body Type Calculator's real height-divided-by-wrist-circumference formula show exactly how three different ratios land in the Ectomorph, Mesomorph, and Endomorph bands.
Read guideBody Type vs. Ideal Body Fat: Why Your Frame Isn't Your Composition
Running the same two people's real measurements through the Body Type Calculator and the Ideal Body Fat Calculator shows why a frame classification and a body-fat category are two independent readings, not steps in one pipeline.
Read guideHow Body Surface Area Is Calculated From Weight and Height
Body surface area comes from the century-old Du Bois formula — weight and height each raised to their own fractional power and multiplied together — still the standard estimate behind clinical medication dosing today.
Read guideHow Your Healthy Weight Range Is Calculated
A healthy weight range comes from inverting the BMI formula at the WHO's normal-BMI cutoffs (18.5 and 25), giving a low and high weight for any given height rather than a single target number.
Read guide