Free Tool
Body Fat % Calculator
Free here • Paid in Coaching apps + clinical DEXA ($50-150)
Pick the method that matches the tools you have. Tape measure only? Use Navy or RFM. Skinfold calipers? Use Jackson-Pollock for the most accurate field estimate. We compute every method that has enough data.
New to body fat percentage? Read the plain-English definition →
What tools do you have?
Recommended estimate
17.5%
body fat
Category: Fitness
All methods compared
Methods that need more inputs are still listed for reference. The most accurate method available is highlighted.
| Method | Body Fat |
|---|---|
US NavyBest fit Hodgdon & Beckett (1984), Naval Health Research Center | 17.5% |
Jackson-Pollock 3-site Jackson & Pollock (1978, 1980) | Needs more inputs |
Jackson-Pollock 7-site Jackson & Pollock (1978, 1980) | Needs more inputs |
Covert Bailey Bailey C (1991), The New Fit or Fat | 12.3% |
RFM (Woolcott-Bergman) Woolcott & Bergman (2018), Sci Rep 8:10980 | 22.8% |
Track body fat changes over months in Zealova
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Methodology + Sources
- Hodgdon JA, Beckett MB (1984). Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center.
- Jackson AS, Pollock ML (1978). Generalized equations for predicting body density of men. Br J Nutr 40(3):497-504.
- Jackson AS, Pollock ML, Ward A (1980). Generalized equations for predicting body density of women. Med Sci Sports Exerc 12(3):175-81.
- Siri WE (1961). Body composition from fluid spaces and density. UC Berkeley Donner Lab Report.
- Woolcott OO, Bergman RN (2018). Relative Fat Mass (RFM) as a new estimator of whole-body fat percentage. Sci Rep 8:10980.
- Bailey C (1991). The New Fit or Fat.
Last updated: 2026-05-14
Built by Sai, founder of Zealova. Not a neutral third party. Calculator results are estimates. For medical decisions, consult a qualified professional.
Frequently asked questions
Which method is most accurate?+
For field methods, Jackson-Pollock 7-site skinfold is the most accurate, with a standard error around 3 percent. The 3-site shortcut is nearly as good at around 3 to 4 percent. Navy circumference is around 3 to 4 percent for trained users but loses accuracy at the extremes. RFM is the newest and correlates well with DEXA for general populations.
Do I need calipers?+
For Navy and RFM, no. A flexible tape measure is enough. For Jackson-Pollock methods, yes, you need skinfold calipers and ideally another person to take the measurement. Calipers cost around 10 to 30 dollars on Amazon.
How often should I measure?+
Every 2 to 4 weeks. Body fat changes slowly. Daily or weekly measurements are dominated by measurement noise and hydration shifts, not real change. Take 3 readings per site and average them.
Why do the methods disagree by 3 to 6 percent?+
Each was fit on a different study population and a different gold standard reference (hydrostatic weighing or DEXA). The disagreement is your real measurement uncertainty. Track trends from one method, not absolute values across methods.
How does this compare to DEXA?+
DEXA is around 1 to 2 percent accurate, the clinical gold standard, but costs 50 to 150 dollars per scan. Skinfold methods correlate well with DEXA at typical body fat ranges. They lose accuracy below 6 percent or above 35 percent.
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