Body fat percentage tells you something weight alone cannot: how much of you is tissue that burns energy, and how much is tissue that stores it. Two people at 72 kg can sit twelve percentage points apart.
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How to take the measurements
Use a soft tape, keep it level, and do not pull it tight enough to compress the skin. Measure in the morning before eating.
- Neck: just below the larynx, tape sloping slightly down at the front
- Waist: at the navel for men, at the narrowest point for women
- Hip: at the widest point, women only
Take each one twice and use the average. A centimetre of error at the waist moves the result by roughly one percentage point.
What the method can and cannot do
This is the US Navy circumference method. It was built to screen large groups cheaply, not to give laboratory precision, and it typically lands within three to four percentage points of a DEXA scan. It reads least accurately at the extremes, so a very lean or very heavy result should be treated as a rough bracket. What it does well is track change: if your waist drops two centimetres while weight holds, that shows up here, and the scale would have shown nothing.
Why the ranges differ for men and women
Women carry more essential fat, which is required for normal hormone function rather than stored as surplus. That is why a woman at twenty-two percent sits in a fit range while a man at the same figure sits in an average one. Reading a woman against male ranges is a common mistake and it produces a conclusion that is wrong in a way that matters.
Waist matters on its own
Total body fat and where it sits are two separate questions, and the second one carries more metabolic weight. Fat around the organs behaves differently from fat under the skin, which is why the waist to height ratio appears alongside your result. Below 0.5 is the usual reference point. Someone can sit in an average body fat range with a waist to height ratio above that, and the waist figure is the one to act on.
When a measurement beats an estimate
If you are making decisions off this number, measure it properly instead. A body composition test separates fat, muscle and water directly, which matters most when the goal is keeping muscle while losing weight. A metabolic assessment covers what the tape cannot see at all. To talk it through, book a consultation.
Every iLIV guide is written and reviewed under our editorial standards, and each one carries the name of the reviewing doctor together with their MMC registration number.
