Formula
Metric BMI is kilograms per metre squared. The US customary form multiplies pounds per inch squared by 703 so it matches. Categories are the WHO adult cutoffs.
BMI = kg / m²
BMI = (lb / in²) × 703
150 lb at 65 in is 24.959. 70 kg at 175 cm is 22.857. The bands are under 18.5, 18.5 to 25, 25 to 30, and 30 and above.
Worked examples
150 pounds, 65 inches. (150 / 65²) × 703 = 24.96. Healthy weight, on the WHO cutoff, and close to the line at 25.
70 kilograms, 175 centimetres. 70 / 1.75² = 22.86. Healthy weight.
Reference
WHO adult cutoffs. They are a screening table, not a personal result.
| Band | BMI |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5 to 24.9 |
| Overweight | 25 to 29.9 |
| Obesity | 30 and above |
Questions
How is BMI calculated?
In metric units, weight in kilograms divided by height in metres squared. In US units, weight in pounds divided by height in inches squared, times 703. The 703 is the factor the CDC publishes so the two formulas agree. 150 pounds at 65 inches is a BMI of 24.96.
What are the BMI categories?
The WHO adult cutoffs used here: under 18.5 underweight, 18.5 up to 25 healthy weight, 25 up to 30 overweight, 30 and above obesity. 70 kilograms at 175 centimetres is 22.86, in the healthy-weight band.
Is BMI a diagnosis?
No. It is a screening index. It does not see muscle, frame, age, or health. A high or low number is a reason to talk with a clinician, not a result this site interprets. This is not a medical calculator beyond that screening definition.
Why is this on a site for makers?
The previous calculator.pro had a body-mass page that other sites linked to. The link still lands on a BMI calculator. The rest of this site is shop math.
Sources
- CDC customary formula: (weight in pounds / height in inches²) × 703. Metric: kg / m².
- WHO adult cutoffs: 18.5, 25, and 30. BMI does not diagnose.