Waist-to-Height Ratio Calculator
Check whether your waist is less than half your height. Enter centimetres or inches to receive an instant ratio and plain-English explanation.
Calculate your ratio
Use the same unit for both measurements.
Your result
Your waist measurement is less than half your height.
Waist-to-height ratio, sometimes shortened to WHtR, compares your waist circumference with your height. The calculation is simple: divide waist size by height using the same unit. UK guidance encourages adults with a BMI below 35 to try to keep their waist below half their height.
The measure can help identify central adiposity, meaning fat carried around the middle. It is used alongside BMI and other health information rather than as a standalone diagnosis.
How to measure your waist correctly
Measure on bare skin or over thin clothing. Repeating the measurement once can help catch a misplaced or twisted tape.
Waist-to-height ratio chart
| Ratio | NICE description | General interpretation |
|---|---|---|
| Below 0.40 | Below the central-adiposity reference categories | This measure cannot assess whether someone is underweight or receiving adequate nutrition. |
| 0.40 to 0.49 | No increased central adiposity | Waist is less than half of height. |
| 0.50 to 0.59 | Increased central adiposity | Associated with increased health risks. |
| 0.60 or above | High central adiposity | Associated with further increased health risks. |
These ranges describe population-level risk, not certainty for an individual. Blood pressure, cholesterol, blood glucose, smoking, family history, activity and existing conditions also matter.
Waist-to-height ratio examples
A person who is 170 cm tall with an 80 cm waist has a ratio of 80 ÷ 170 = 0.47. Their waist is below half their height because half of 170 cm is 85 cm.
The calculation works identically in inches. Someone who is 70 inches tall with a 36-inch waist has a ratio of 36 ÷ 70 = 0.51. Units must not be mixed.
Who should not rely on this calculator?
The NHS advises against using its waist-to-height calculator for children under five, during pregnancy, if someone has an eating disorder or thinks they may have one, or when a growth disorder or other condition affects height. Adults with a BMI over 35 should not use the NHS tool for interpretation. Anyone aged 17 or younger should use it with a parent or carer.
If the tool is unsuitable for you, or the result causes concern, speak with a pharmacist, GP surgery or another qualified healthcare professional.
Waist-to-height ratio versus BMI
BMI uses weight and height to group people into broad weight categories, but it does not show where weight is carried. Waist-to-height ratio focuses on the middle of the body. NICE recommends it alongside BMI for assessing central adiposity in relevant adults, including adults with high muscle mass. Neither measurement captures every aspect of health or body composition.
Frequently asked questions
What is a healthy waist-to-height ratio?
NICE classifies 0.40 to 0.49 as no increased central adiposity. The memorable public-health message is to keep your waist below half your height, which means a ratio under 0.5.
How do I calculate waist-to-height ratio?
Divide waist circumference by height using the same unit. An 80 cm waist and 170 cm height gives 80 ÷ 170 = 0.47.
Is waist-to-height ratio better than BMI?
They describe different things. BMI reflects weight relative to height, while waist-to-height ratio considers abdominal size. Guidance uses them together rather than declaring one universally superior.
Does sex change the calculation?
The calculation and NICE adult thresholds do not require sex. Individual health assessment remains more detailed than any single ratio.
Can children use this calculator?
The NHS says anyone aged 17 or younger should use its calculator with a parent or carer, and it should not be used for children under five. Growth assessment is best discussed with a healthcare professional.
Sources
This page follows the NHS waist-to-height ratio guidance and NICE guidance on identifying central adiposity.
Health notice: This calculator provides general information only. It does not diagnose disease, assess every form of health risk or replace individual medical advice. Avoid repeated body checking if measurements cause anxiety or distress, and seek appropriate professional support.