BMI Calculator
Estimate body mass index from height and weight. BMI is a quick screening number, not a complete measure of health or body composition.
BMI formula
Metric: BMI = weight kg / (height m × height m) US: BMI = 703 × weight lb / (height in × height in)
Example
A person who is 178 cm tall and weighs 78 kg has a BMI of about 24.6, which falls near the upper end of the common normal-weight range.
BMI categories
- Below 18.5: underweight range.
- 18.5 to 24.9: normal-weight range.
- 25 to 29.9: overweight range.
- 30 or higher: obesity range.
Limitations
BMI does not distinguish muscle, fat, bone density, pregnancy, age-related body changes, or individual medical history. Use it as a broad screening estimate only.
FAQ
Is BMI a diagnosis?
No. BMI is a screening number. A clinician can interpret it alongside waist size, labs, activity, history, and other health factors.
Can athletes have a high BMI?
Yes. People with high muscle mass can have a high BMI without having the same risk profile as someone with high body fat.
Why offer metric and US units?
Many users search with different measurement systems, so the calculator supports both common input styles.