Body fat calculator
The measurements stay in this tab. Nothing is uploaded or saved.
Body fat
U.S. Navy circumference method (Hodgdon & Beckett, 1984); categories from the ACE ranges.
An estimate for adults, not a medical diagnosis. Measure the same way each time to track change.
How to use this tool
Estimate body fat from a tape measure with the U.S. Navy formula. Nothing is uploaded.
Open Body fat calculator
Metric and male are selected with sample numbers. Body fat and category sit on the right.
Enter your measurements
Height, neck and waist; women also enter hips. Switch to imperial for inches and pounds. Add weight to see fat and lean mass.
Read the result
The percentage and ACE category update as you type. Copy puts them on the clipboard.
FAQ
How is body fat estimated here?
With the U.S. Navy circumference method: height, neck and waist for men, plus hips for women, go into a logarithmic formula. Add weight to split the result into fat mass and lean mass.
Is anything uploaded?
No. The measurements stay in this tab and are not stored.
Where do I measure?
Neck just below the larynx, tape sloping slightly down to the front. Waist at the navel for men and at the narrowest point for women. Hips at the widest point. Keep the tape snug but not tight.
How accurate is it?
Usually within 3 to 4 percentage points of a DEXA scan for most adults, less for very muscular or very lean people. Measure in the morning and repeat the same way to track change over time.
What are the categories?
The ACE ranges: for men essential 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25%+; for women essential 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, obese 32%+.