Body Fat Percentage Calculator
Enter waist, hips, and height. 81, 80, and 175 give 12.6. 91, 90, and 180 give 11.8. 86, 85, and 165 give 14.3. Waist must be larger than hips. Otherwise log10 blanks out and the result shows 0.
Results
Enter data and click Calculate.
Not a clinic verdict and not DEXA. The result has one decimal place from log10(waist minus hip). The Navy calculator next door uses another field set.
How it works
Body fat percentage in this calculator is 495 / (1.0324 − 0.19077 × log10(waist − hip) + 0.15456 × log10(height in metres)) − 450. Waist 81, hip 80, and 175 cm give 12.6 in the result. 91, 90, and 180 give 11.8. 86, 85, and 165 give 14.3. The calculator clamps the result to 0-60.
The fields are bf-talia, bf-biodra, and bf-wzrost. Waist must exceed hip. Equal girths or a larger hip make log10 of zero or a negative, then a blank value and 0. A 10 cm gap at 90 and 80 already hits 60.
This is a Navy-like estimate, not the full US Navy formula with neck. The Navy fat card uses another girth set. There is no neck here. 12.6 is not a skinfold and not DEXA.
Units are cm in metric. With a US header the fields are inches. The 12.6, 11.8, and 14.3 examples are from centimetres. The element holds a bare number, and the % sign sits beside it.
Enter a waist larger than hip, enter height, then Calculate. A comma in 81.5 parses. Zero height breaks log10 and falls to 0. A estimate from a logarithm, not a doctor note.
81, 80, and 175 give 12.6. 91, 90, and 180 give 11.8. 86, 85, and 165 give 14.3. A small waist-hip gap keeps the result in the middle of the scale.
BF = 495 / (1.0324 − 0.19077 × log10(waist − hip) + 0.15456 × log10(hM)) − 450
BF from log10(waist minus hip). 81, 80, and 175 give 12.6. Waist must be larger.
12.6
11.8
14.3
Related calculators
Common questions
What BF at waist 81, hip 80, and 175 cm?
12.6. The formula uses log10(81 − 80) and log10(1.75), then one decimal place.
What about 91, 90, and 180?
11.8. Waist is 1 cm larger than hip again.
What about 86, 85, and 165?
14.3.
What if hip is larger than waist?
log10 of a negative is a blank value. The calculator writes 0. Waist must exceed hip.
What about a 10 cm gap, for example 90 and 80?
The result rises and clamps to 60. A small gap keeps 12.6.
Is this the same formula as the Navy calculator?
No. That card uses neck. Here log10(waist minus hip) and height, with no neck.
Is 12.6 a DEXA reading?
No. A estimate from a logarithm. Not a clinic verdict.
Does a comma in 81.5 work?
Yes. 81.5, 80, and 175 run through the same function.
Does a US header change 81 and 80?
Yes. Then the fields are inches. The 12.6 examples are metric.
How do I calculate body-fat percent from waist and hips?
The calculator uses height and the waist–hips difference (waist must be larger). Example: 81, 80, and 175 cm give 12.6%. 91, 90, and 180 give 11.8%. 86, 85, and 165 give 14.3%.
Is this the full US Navy method?
No. It is a simplified Navy-like estimate without neck circumference. The full neck set lives on the Navy body-fat page.
Why must waist be larger than hips?
The formula uses log10(waist − hips). When waist is not larger, the difference is not positive, the log breaks, and the result drops to 0.
Is 12.6% a DEXA or skinfold reading?
No. It is an estimate from circumference logs and height. It does not replace DEXA, calipers, or clinical advice.
Knowledge sources
Percent from log10(waist minus hip). This is a tape estimate, not DEXA and not the Navy set.
Page updated in 2026.