BMI Calculator
Enter your height and weight in metric (cm, kg) or imperial (in, lb) units and get your Body Mass Index instantly. Your result comes with the standard weight category so you can see where you land.
BMI
Calculate your Body Mass Index from height and weight.
FAQs
What is a healthy BMI?
A BMI between 18.5 and 24.9 is classified as the healthy range. It is a screening tool, not a diagnosis — muscle mass, age, and body composition can all shift what a given BMI means for you.
Does this calculator work with feet, inches, and pounds?
Yes. Enter your height in inches and weight in pounds, and the imperial formula (with the 703 factor) is applied. You can also use centimeters and kilograms for the metric formula — both give the same result.
How it works
BMI is your weight divided by your height squared. In metric units that is weight in kilograms divided by height in meters squared. For example, a person who is 175 cm tall and weighs 70 kg has a BMI of 70 ÷ (1.75 × 1.75) ≈ 22.9.
In imperial units the formula multiplies by 703: weight in pounds divided by height in inches squared, times 703. So at 5'9" (69 in) and 155 lb: 703 × 155 ÷ (69 × 69) ≈ 22.9.
Standard categories are: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, and 30 or above obese. The calculator shows your category automatically — pick whichever unit system you are comfortable with.
What BMI actually measures
BMI is a ratio of weight to height, and nothing more. It does not know whether the weight comes from muscle, bone, or fat, which is why very athletic people can land in the "overweight" band while being perfectly fit.
Treat it as a first-pass screening number. If it puts you in a category that surprises you, look at waist size, activity level, and how you feel before drawing conclusions.
Why the 18.5 to 24.9 band matters
Large population studies link the 18.5–24.9 range with the lowest average health risks, which is why it is labeled "healthy." Risk tends to rise as BMI moves well above or below that band.
Still, averages are not individuals. Someone at 25.5 who exercises daily may be healthier than someone at 22 who does not — use the band as a reference point, not a verdict.
Making the number useful
Recalculate every few months rather than daily; BMI moves slowly and daily noise is meaningless. Log it alongside habits — sleep, steps, meals — so you can see what actually shifts the number.
If your BMI sits outside the healthy range and stays there, that is simply information worth acting on. Small, steady changes in diet and movement move BMI more reliably than crash efforts.