Body Fat Calculator

Estimate body fat percentage using Navy tape measurements, BMI estimators, or skinfold calipers.

Weight (kg)

Height (cm)

Age (years)

Neck Circumference (cm)

Waist Circumference (cm)

Body Fat %

18.0%

Fitness

Fat Mass:14.4 kg

Lean Mass:65.6 kg

Target Body Fat Weight Calculator

Estimate how much weight you need to adjust to reach your target body fat percentage, assuming your current lean body mass is fully preserved.

Target Body Fat %

Goal Weight

77.2 kg

Calculation Logic:Since your lean mass is 65.6 kg, reaching 15% fat mass implies that your lean mass accounts for 85% of your total target body weight.

About Body Fat Percentages & Formulas

Body fat percentage represents the total mass of fat divided by total body mass. This tool utilizes three standard estimation methods:

U.S. Navy Tape Method: Uses neck and waist circumference (plus hip for females) relative to height. A highly accessible standard.
BMI-based Estimator: Uses age, gender, and BMI (weight/height) for a quick backup estimate.
Jackson-Pollock 3-Site Caliper: Measures skinfold pinch thickness at three distinct sites. Highly accurate for lean/athletic statures.

Built and maintained by Meet Shah · Last updated 1 August 2026

What this tool is used for

Estimating body fat from tape measurements using the Navy method.
Getting lean and fat mass figures alongside the percentage.
Tracking a change over months rather than reacting to one reading.
Comparing a tape estimate against a scale's own figure.
Producing a number to discuss with a coach.

Frequently Asked Questions

How does the Navy tape method work?: It regresses body fat on circumference measurements relative to height — neck and waist for men, plus hips for women — through a logarithmic formula from the Naval Health Research Center. The logarithms are why precision matters: half an inch at the waist moves the result by about a percentage point.
How accurate is it?: Within about 3–4 percentage points against hydrostatic weighing for most people, which is respectable for a tape measure. It performs worst on very lean and very obese subjects, and on anyone whose fat distribution differs from the population it was fitted to.
Where exactly should the measurements be taken?: Waist at the navel for men and at the narrowest point for women, hips at the widest, neck just below the larynx — and the tape snug without compressing. Consistency matters more than technique: comparing two measurements taken differently is worse than a slightly wrong method used the same way twice.
What is a healthy body fat percentage?: Roughly 10–20% for men and 18–28% for women, with essential fat at about 3% and 12% respectively — the floor below which normal function is impaired. Athletes commonly sit below the general range, and the sex difference is physiological rather than a matter of conditioning.
Which method should I trust?: DEXA for a single accurate number, and consistency for tracking change. Bioimpedance scales swing several points with hydration alone, which makes them poor for a snapshot and acceptable for a trend if measured under identical conditions each time.

Common errors and gotchas

Measuring inconsistently, which is the largest error source — same time, same tension, same landmarks.
Treating a tape estimate as a scan, where the method has a meaningful error band.
Comparing figures from different methods, which are not interchangeable.
Pulling the tape tight, which compresses tissue and understates the measurement.
Reading one measurement as a trend, when the method's error band exceeds a week's change.