Weight & Body tool
Waist-to-Height Ratio Calculator
Work out your waist-to-height ratio in cm or inches and see whether your waist is less than half your height, the limit advised by NICE. Free, nothing stored.
Nothing you enter leaves your device.
Inputs
Results
Enter values to see your results.
Simple steps
How it works
- 01
Choose metric or imperial units.
- 02
Enter your height and your waist measurement.
- 03
Select Calculate to see your ratio and how it compares with 0.5.
Good to know
Frequently asked questions
What is the waist-to-height ratio?
Your waist measurement divided by your height, in the same units. A waist of 80 cm and a height of 170 cm give a ratio of 0.47.
What ratio should I aim for?
Under 0.5, in other words a waist less than half your height. The UK National Institute for Health and Care Excellence (NICE) uses this simple message for adults.
Why use it as well as BMI?
BMI does not show where fat is stored. Fat around the waist matters more for health, and the waist-to-height ratio reflects it directly.
How do I measure my waist?
Measure halfway between your lowest rib and the top of your hip bone, after breathing out, with a tape measure that is snug but not tight.
Who is it not suitable for?
It is not meant for pregnancy or for children under 5. It can be less reliable for some athletes and people with a very large frame.
Is anything I enter stored or sent?
No. The calculation runs in your browser. Nothing you type is saved or sent to a server.
How it is calculated
Ratio = waist ÷ height, both in the same unit. Bands follow Ashwell and colleagues: below 0.4; 0.4 to 0.49; 0.5 to 0.59; 0.6 or more. NICE advises adults to keep the ratio below 0.5.
Sources
- Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI. Obes Rev 2012;13:275–86
- National Institute for Health and Care Excellence. NG246: Overweight and obesity management (2025)
Last reviewed: October 14, 2026