Body Fat Calculator | Body Fat Percentage

Quick Start Guide

  1. Enter Age and Gender: Input your age and select your gender, as measurement requirements differ.
  2. Enter Height: Input your height in the selected unit system (metric or imperial).
  3. Measure Neck: Measure around your neck at the narrowest point and enter the value.
  4. Measure Waist: Measure around your waist at the navel level and enter the value.
  5. Measure Hips (Women): For women, measure around the widest part of your hips and enter the value.
  6. View Results: See your estimated body fat percentage and category (athletic, fitness, average, etc.).
  7. Optionally Set a Target: Set a target body fat percentage for goal tracking.

Understanding Body Fat %

The US Navy circumference method

This calculator estimates body fat percentage from tape-measure circumferences (neck, waist, and — for women — hip) rather than expensive equipment. It is a validated field method, typically accurate to within ±3–4 percentage points versus a DEXA scan, the clinical gold standard.

Fat mass and lean mass

Once body fat % is known, multiplying it by total body weight gives fat mass; the remainder is lean mass (muscle, bone, organs, water). Tracking lean mass alongside the percentage helps distinguish fat loss from muscle loss when weight changes.

Reading the category chart

Category ranges (essential, athletic, fitness, average, obese) differ by sex because women carry more essential fat than men. The same percentage that is "average" for a woman would be classified differently for a man — this calculator always applies the correct chart for the selected gender.

Limitations to keep in mind

The Navy method assumes a typical fat-distribution pattern and can be less accurate for people with unusually muscular builds or atypical body-fat distribution. For a more precise reading, consider a DEXA scan, BIA scale, or hydrostatic weighing — treat this estimate as a convenient tracking tool, not a diagnostic measurement.

Features

US Navy Method: A common formula that estimates body fat percentage using body measurements.

Category Display: See which body fat category you fall into based on your percentage.

Progress Tracking: Track your body fat percentage over time with an interactive chart.

Goal Setting: Set a target body fat percentage and track your progress gap.

Export Data: Export your calculations to JSON, CSV, or PDF format.

Common Use Cases

Fitness Goals: get your body fat % and category (e.g. athletic, fitness, average), and set a target body fat % to see fat-to-lose and progress context.

Health Check: estimate body fat from waist, neck, hip, and height, and see which health category you fall into.

Weight Loss: track body fat % over time with a progress chart and compare with BMI or other metrics.

Athletic Performance: monitor body composition for sport or training, and export or copy results for logs.

Frequently Asked Questions

The US Navy method (using tape measurements) is generally more accurate than BMI because it accounts for body composition (waist/neck size) rather than just height and weight. BMI cannot distinguish muscle from fat.
Waist: Measure at the navel (belly button) level, keeping the tape horizontal and snug but not compressing the skin. Neck: Measure just below the Adam's apple (larynx). For women, also measure hips at the widest point. Measure in the morning before eating for most consistent results.
For men: Essential fat 2-5%, Athletes 6-13%, Fitness 14-17%, Acceptable 18-24%, Obese 25%+. For women: Essential 10-13%, Athletes 14-20%, Fitness 21-24%, Acceptable 25-31%, Obese 32%+. These ranges are general guidelines; consult a health professional for personalized assessment.
The US Navy method has a margin of error of about ±3-4% compared to DEXA scan (gold standard). It is more accurate than BMI but less precise than hydrostatic weighing or DEXA. Accuracy improves with careful, consistent measurements taken multiple times and averaged.
Our calculator uses the US Navy method, which estimates body fat percentage using body measurements. For men, it uses height, neck, and waist measurements. For women, it adds hip measurements. This method provides a reasonable approximation without specialized equipment.
Measure body fat every 2-4 weeks for progress tracking. More frequent measurements may show fluctuations due to hydration, food intake, or measurement technique. Consistent timing and conditions improve tracking accuracy.
Yes. Our calculator includes progress tracking features. Set a target body fat percentage and track your progress over time. The calculator shows your current BFP, target BFP, and the difference needed to reach your goal.

Last updated