Example 1
- waist 81 cm
- hip 80 cm
- 175 cm
12.6
What BF at waist 81, hip 80, and 175 cm? 12.6. Waist must exceed hip.
Body fat percentage calculator
Type waist, hip, 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 exceed hip. Otherwise log10 is a blank value and the calculator writes 0.
Not a clinic verdict and not DEXA. The result has one decimal place from log10(waist minus hip). The Navy card next door uses another field set.
Results
Enter data and click Calculate.
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 sketch, 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.
Type a waist larger than hip, type height, then Calculate. A comma in 81.5 parses. Zero height breaks log10 and falls to 0. A sketch 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.
Formula
BF = 495 / (1.0324 − 0.19077 × log10(waist − hip) + 0.15456 × log10(hM)) − 450
How to use
- Type waist in cm larger than hip, for example 81.
- Type hip, for example 80, and height 175.
- Click Calculate. The result is 12.6.
- 91, 90, and 180 give 11.8. 86, 85, and 165 give 14.3.
- The Navy formula with neck lives on the fat card. Here log10(waist minus hip).
81, 80, and 175 = 12.6
BF from log10(waist minus hip). 81, 80, and 175 give 12.6. Waist must be larger.
- waist
- Field bf-talia. It must exceed hip. 81 with 80 and 175 gives 12.6.
- hip
- Field bf-biodra. 90 with waist 91 and 180 cm gives 11.8. A larger hip gives 0.
- log10
- The log of waist minus hip. 86 minus 85 at 165 cm gives 14.3. a blank value falls to 0.
Examples
Example 2
- waist 91 cm
- hip 90 cm
- 180 cm
11.8
What BF at 91, 90, and 180 cm? 11.8. Waist is 1 cm larger again.
Example 3
- waist 86 cm
- hip 85 cm
- 165 cm
14.3
What BF at 86, 85, and 165 cm? 14.3. Equal girths would give 0.
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 card?
No. That card uses neck. Here log10(waist minus hip) and height, with no neck.
Is 12.6 a DEXA reading?
No. A sketch 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.
Knowledge sources
Percent from log10(waist minus hip). This is a tape estimate, not DEXA and not the Navy set.
Page updated in 2026.