📏 Body Fat Percentage Estimator

Three methods. One number. Your choice. All calculations run in your browser — we never see your data.

Navy Method (Circumference)

Uses neck and waist measurements. Fast, no equipment beyond a tape measure.

How It Works

This estimator combines three validated methods to give you a range of body fat percentages. The Navy Method uses neck and waist circumference — fast, free, and requires only a tape measure. The YMCA Method simplifies further with just weight and waist. The Jackson-Pollock Skinfold method uses caliper measurements at 3 or 7 sites and is the most accurate home option when performed correctly. Each method has known error margins (shown in your results). We recommend using 2-3 methods and comparing the range rather than trusting any single number.

Navy Method
Error: ±4-6%
Needs: Tape measure
YMCA Method
Error: ±5-8%
Needs: Scale + tape
3-Site Skinfold
Error: ±4-6%
Needs: Calipers + skill
7-Site Skinfold
Error: ±3-5%
Needs: Calipers + experience

Tip: Measure at the same time of day, under the same conditions. Hydration and meal timing can shift readings by 1-3%.

📊 Saved Results

Compare your measurements over time. Data is stored locally in your browser.

No saved results yet. Calculate and save to start tracking.

Recommended Tools

⚖️ BMI vs Body Fat Analyzer

See how your BMI and body fat compare.

💪 Lean Body Mass Calculator

Calculate lean mass from your results.

📝 Skinfold Tracker

Log your skinfold measurements over time.

Frequently Asked Questions

Q: Which method is most accurate?

The Jackson-Pollock 7-site skinfold method is the most accurate home option (±3-5% error). The Navy Method is fastest but less precise (±4-6%).

Q: Do I need calipers for the skinfold method?

Yes, you need a pair of skinfold calipers. A basic Lange or Harpenden-style caliper costs $15-30. Self-measurement adds about ±8% error.

Q: Why do my results differ between methods?

Each method measures different things and uses different equations. Navy uses circumference, YMCA uses weight+waist, skinfold measures fat thickness. Use 2-3 methods and compare the range.

Q: Is this a medical measurement?

No. These are estimates based on population equations. For medical-grade accuracy, get a DEXA scan (±1-2% error).