Trim & Thriving Free calculator
One tape, one number

Half your height. That is the whole rule.

Keep your waist under half your height. It sounds too simple to be worth anything, and it out-predicts BMI for the risks that matter, because it notices where fat sits rather than only how much of it there is.

0.50
The line drawn for every adult

The same threshold for a tall frame and a short one, for twenty and for sixty. Useful as a rule of thumb, and not a measurement of you.

The rule
0.50
You
0
0Where you sit
0Waist at 0.5
0Difference

The arithmetic runs in your browser. Nothing is sent anywhere.

Method
Waist circumference divided by height, both in the same unit. Under 0.5 is the threshold in common use.
How to measure
Standing, breathing out normally, tape level with the floor, snug without compressing. Measure in the morning for consistency, and always the same way.
Limits
A general educational estimate, not medical advice. Needs shift with health conditions, medication and training history.

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