Estimate your body fat from a few tape measurements, your waist alone, or your BMI, and see where it sits in the healthy range for your age and sex.
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The formulas use different numbers for female and male bodies.
In years, 20 or over. The healthy range shifts with age.
Use a soft tape, snug but not pressing into the skin.
Just below the Adam's apple, with the tape level.
Relaxed, after a normal breath out. Women: at the narrowest point. Men: level with the navel.
Around the widest part of your hips and buttocks.
Enter your details to see your result.
Choose one under How to measure.
US Navy tape, the default, comes from Hodgdon and Beckett's 1984 work for the US Navy1. Their equations use inches, so the calculator converts centimetres first:
Men measure the waist level with the navel. Women measure it at the narrowest point, plus the hips at the widest. The neck goes just below the Adam's apple.
Waist only uses relative fat mass, from Woolcott and Bergman2. They built it on 12,581 US adults and tested it against DXA scans in 3,456 more, where it beat BMI:
No tape estimates body fat from BMI, age and sex with the equation of Gallagher and colleagues3, where male is 1 for men and 0 for women:
There's no official body fat scale. Gallagher's team measured 1,626 adults with reference methods and tied body fat to the BMI cut-offs instead3. The calculator follows them. Your healthy range is what their equation gives at BMI 18.5 and 25 for your age and sex, and high starts at the BMI 30 value, so the range shifts with age. Past 79, the 79-year range applies.
"Typical at your BMI" is the same equation at your own BMI. A result below it draws the figure leaner, and a result above it draws it softer.
If you entered a waist, you also get your waist-to-height ratio. NICE treats 0.4 to 0.49 as healthy, 0.5 to 0.59 as increased risk and 0.6 or more as high risk4.
Tape formulas are estimates. In fit US Marines the circumference method read men about 2.5 points low and women 1.3 to 2.3 points high compared with DXA scans, and it read lean people high and people with more fat low5.
Tip
Pull the tape snug without pressing in, measure on bare skin, and stick to one formula if you're tracking change.
No tape uses Gallagher's equation for white and Black adults. Asian adults tend to carry more body fat at the same BMI36, so for them it probably reads low.
Warning
This is for adults aged 20 and over, and it isn't meant for use during pregnancy.
Hodgdon JA, Beckett MB (1984). Prediction of percent body fat for U.S. Navy men from body circumferences and height (Report 84-11), and Prediction of percent body fat for U.S. Navy women from body circumferences and height (Report 84-29). Naval Health Research Center, San Diego. ↩
Woolcott OO, Bergman RN (2018). Relative fat mass (RFM) as a new estimator of whole-body fat percentage: a cross-sectional study in American adult individuals. Scientific Reports 8:10980. ↩
Gallagher D, Heymsfield SB, Heo M, Jebb SA, Murgatroyd PR, Sakamoto Y (2000). Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. American Journal of Clinical Nutrition 72(3):694-701. ↩ ↩2 ↩3
National Institute for Health and Care Excellence (2025). Overweight and obesity management. NICE guideline NG246. ↩
Potter AW, Tharion WJ, Holden LD, Pazmino A, Looney DP, Friedl KE (2022). Circumference-based predictions of body fat revisited: preliminary results from a US Marine Corps body composition survey. Frontiers in Physiology 13:868627. ↩
WHO Expert Consultation (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. The Lancet 363(9403):157-163. ↩
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