BMI Calculator
Body Mass Index is a quick screening number that compares your weight to your height. Enter your measurements in US or metric units to see your BMI and the healthy range for your height.
BMI divides your weight by the square of your height. In US units the formula multiplies by 703 to convert pounds and inches into the same scale as the metric version, so both give the same number.
The standard adult categories are: below 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30 or above obese. BMI is a screening tool, not a diagnosis — it does not account for muscle mass, bone density or body composition, so athletes and very muscular people may read high.
Worked examples
US units
A person who is 5′10″ and 170 lb: 703 × 170 ÷ 70².
→ BMI 24.4 — healthy weight
Metric units
A person who is 178 cm and 77 kg: 77 ÷ 1.78².
→ BMI 24.3 — healthy weight
Healthy range
At 5′6″ (66 in), the healthy BMI band of 18.5–24.9 corresponds to roughly 115–154 lb.
→ 115 – 154 lb