Waist-to-height calculator (BMI)
A tape measure and three inputs: calculate your waist-to-height ratio and BMI. These values offer guidance, not a diagnosis.
Your measurements
Your guide
Waist / height
Body mass index (BMI)
kg/m²
Calculated from your inputs. Classification uses unrounded values.
How to measure your waist
Locate the bottom of your ribs and the top of your hip bone. Wrap the tape horizontally around your waist halfway between them. Stand relaxed and read after breathing out normally. The tape should fit snugly without compressing your skin. Measure against bare skin if possible.
Use the same technique for comparisons. Small differences can reflect measurement error, meals or time of day.
What the values mean
The ratio is waist circumference divided by height in the same units. For adults with BMI below 35, NICE uses these bands: 0.40 to below 0.50 indicates no increased risk from central adiposity, 0.50 to below 0.60 indicates increased risk, and 0.60 or above indicates further increased risk. This tool does not assign a risk category below 0.40.
BMI does not account for muscle mass or fat distribution. Waist-to-height ratio does not directly measure body fat or determine overall health. Individual risks also depend on blood pressure, blood tests, medical conditions and family history.
At BMI 35 or above, the ratio is shown without classification using these thresholds. Discuss an appropriate assessment with a clinician. Input limits are technical plausibility checks.
Sources and measuring guidance
NICE: Waist-to-height ratio · NHS: Waist-to-height calculatorQuestions and answers
Is waist-to-height ratio the same as BMI?
No. Waist-to-height ratio divides waist circumference by height. BMI divides weight in kilograms by height in metres squared. This calculator shows the values separately.
What information do I need?
Enter height, weight and waist circumference. Follow this page’s measuring instructions and eligibility guidance. One number cannot replace individual assessment.