About the Body Adiposity Index Calculator
The body adiposity index, or BAI, estimates body fat percentage from your hip circumference and your height. It does not need your weight, so it can be used when no scale is available. This calculator takes both measurements in centimetres. Type hip circumference and height in centimetres and the body adiposity index appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Body Adiposity Index Calculator
- 1Enter hip circumference and height in centimetres.
- 2Pick the units or options from the menus if the body adiposity index tool offers them.
- 3Read the body adiposity index in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the body adiposity index
People use it for a rough body fat estimate when they have only a tape measure.
It was developed for adults, and its accuracy is lower than that of other methods. Compare it with other measures such as BMI and waist-to-height ratio.
How the body adiposity index is worked out
BAI = hip circumference in cm ÷ (height in m)^1.5 − 18. A hip of 98 cm on a person 175 cm tall: 98 ÷ 2.315 − 18 = 24.3, an estimated body fat of about 24%.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- No weight needed
- Quick result
- Hip and height only
Mistakes to avoid with body adiposity index
Measure at the widest part of the hips, and do not use it for children or athletes. Treat the result as a rough guide and talk to a doctor about health decisions.
On phone and computer
On a phone, type into the boxes one after another and read the body adiposity index underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the body adiposity index move. The body adiposity index calculator works the same on both.
Checking your body adiposity index by hand
A good habit is to test the body adiposity index calculator with a case you already know. A hip of 98 cm on a person 175 cm tall: 98 ÷ 2.315 − 18 = 24.3, an estimated body fat of about 24%.
If your own figures give a surprising answer, repeat the working yourself: BAI = hip circumference in cm ÷ (height in m)^1.5 − 18. Small differences usually come from rounding, from mixing units, or from a typing slip in one of the inputs. No single body number tells the whole story, so compare a few. Try the Body Fat Calculator for another estimate, the BMI Calculator for the familiar figure, and the Waist-to-Hip Ratio Calculator for where weight is carried.
Features
- Rough estimate
- Adults only
- Measure the widest hip
- Clear messages when the body adiposity index inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate body adiposity index?
BAI = hip circumference in cm ÷ (height in m)^1.5 − 18. A hip of 98 cm on a person 175 cm tall: 98 ÷ 2.315 − 18 = 24.3, an estimated body fat of about 24%.
What is the formula for body adiposity index?
BAI = hip circumference in cm ÷ (height in m)^1.5 − 18. The body adiposity index calculator applies it exactly and rounds only the displayed answer to six significant figures.
Is BAI accurate?
It is a rough estimate and can differ from scan-based methods.
Does it need weight?
No. Only the hips and the height.
Does it differ for men and women?
The original formula is the same for both.
Is this body adiposity index calculator free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.