The calculation runs in your browser; no data is sent or stored. The result is for information only and does not replace assessment by your doctor.
What does the body fat calculator measure?
The calculator estimates what percentage of your weight is fat, using a few circumferences and your height. The method is based on the Hodgdon-Beckett formula. For men, the formula uses the neck and waist; for women, it also adds the hips, where fat is distributed differently.
The result is an estimate, not a measurement. Compared with reference methods such as hydrostatic weighing, the formula can be off by a few percentage points, and the error grows at high values [1]. The figure is still useful as a starting point and as a trend over time (with the same tape measure). The colored badge under the result groups the five ranges below into three. Below 6% in men and below 14% in women it reads Low range, which covers only essential fat. From there up to just under 25% in men and up to and including 35% in women it reads Reference range. From 25% in men and above 35% in women it reads Obesity range.
How do you take the measurements correctly?
You need a flexible tape measure and a mirror. Keep the tape horizontal, flat against the skin, but without pulling it tight. Measure in the morning, before a meal, then write the figures down so you can compare them in a few months.
- the neck — just below the Adam's apple, with the tape sloping slightly forward;
- the waist — in men at the level of the navel, in women at the narrowest point;
- the hips — in women, at the widest point, over the buttocks;
- height — barefoot, with your back against the wall.
Measure twice and use the average. Breathe normally and do not pull your stomach in while you measure, otherwise the result will look better than it really is.
What body fat percentage is normal?
Reference values differ between men and women, because a woman's body needs more essential fat. The ranges in common use are:
- essential fat — 2–5% in men, 10–13% in women;
- athletic range — 6–13% in men, 14–20% in women;
- good range — 14–17% in men, 21–24% in women;
- acceptable range — 18–24% in men, 25–35% in women;
- obesity range — 25% or more in men, over 35% in women [2].
The colored badge under the result groups these categories into three, so they are easy to read. Below essential fat the body no longer has the reserve it needs for hormones and for temperature, so an extremely low percentage is not a good result.
Why does body fat matter in diabetes?
It is not the total amount of fat that matters most, but where it sits. Fat around the abdominal organs releases fatty acids and inflammatory substances straight to the liver. This raises insulin resistance far more than subcutaneous fat on the thighs does.
That is why the waist sometimes says more than the scale. Two people with the same body mass index can have very different risks, depending on how much of their fat sits in the abdomen. Weight loss reduces abdominal fat first, so the benefit for blood glucose appears quickly.