Calculate your Body Mass Index instantly
Add this BMI Calculator to your website or blog for free — just paste this code:
This BMI calculator estimates your Body Mass Index from your height and weight in either metric or imperial units, and shows which standard category the result falls into. It is a quick screening tool for adults who want a general sense of whether their weight sits in a healthy range for their height.
Body Mass Index is your weight divided by the square of your height. In metric units the formula is BMI = weight (kg) ÷ height (m)2; in imperial units it is BMI = 703 × weight (lb) ÷ height (in)2. The tool converts your inputs automatically and returns a single number you can compare against the widely used World Health Organization ranges.
Those ranges are: below 18.5 is underweight, 18.5 to 24.9 is a normal or healthy weight, 25 to 29.9 is overweight, and 30 or above is in the obese range. BMI is a population-level screening measure — it does not distinguish muscle from fat, so athletes and very muscular people may read as overweight despite low body fat.
A BMI between 18.5 and 24.9 is generally considered a healthy weight for most adults. Below 18.5 is underweight and 25 or higher is overweight, though these are guidelines rather than a diagnosis.
Not entirely. BMI does not account for muscle mass, bone density, or fat distribution, so athletes may score high and older adults may score deceptively low. Use it as a starting point alongside other health measures.
Divide your weight in kilograms by your height in metres squared, or multiply your weight in pounds by 703 and divide by your height in inches squared. This calculator handles both units for you.
No. Children and teens are assessed with age- and sex-specific BMI percentile charts rather than the fixed adult ranges, so consult a paediatric growth chart or a doctor.