Nutrition1 min read·Updated March 9, 2026
How to Calculate Body Fat Percentage: Methods and Accuracy
Compare body fat measurement methods — Navy method, calipers, DEXA, bioelectrical impedance — with accuracy ratings and how to use each.
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Why Body Fat Percentage Matters
Body fat percentage is a more useful health metric than weight alone because it distinguishes between fat mass and lean mass (muscle, bone, organs). Two people at the same weight can have dramatically different health profiles based on body composition.
Measurement Methods
- Navy Method (circumference): Free, easy, no equipment. Error: ±3–4%. Good for tracking trends.
- Skinfold Calipers: Error: ±3–5% with good technique. Inexpensive.
- Bioelectrical Impedance (BIA): Bathroom scales. Error: ±3–8%, variable with hydration.
- DEXA Scan: Gold standard. Error: ±1–2%. Costs $50–200.
Body Fat Percentage Categories
- Men: Essential 2–5% | Athletic 6–13% | Fitness 14–17% | Acceptable 18–24% | Obese 25%+
- Women: Essential 10–13% | Athletic 14–20% | Fitness 21–24% | Acceptable 25–31% | Obese 32%+
Tracking Progress
Use one consistent method and track trends rather than absolute values. Measure under consistent conditions — morning, before eating, same hydration state. Don't switch between methods; each gives systematically different numbers.
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Frequently Asked Questions
What's the most accurate body fat method at home?
The Navy circumference method is the most practical accurate option for home use. Consistent measurement technique matters more than the method. Take 3 measurements at each site and average them. Measure at the same time of day each time.
How often should I measure body fat?
Monthly is sufficient for most purposes. More frequent measurement adds noise without signal, since day-to-day water fluctuations can swing readings by 2–3%.