General tools
BMI calculator
Enter your height and weight to get your Body Mass Index and WHO weight category. Everything runs in your browser - nothing is uploaded.
How it works
Body Mass Index is a quick screening number that relates your weight to your height. Enter your height and weight - switch between metric (centimetres and kilograms) and imperial (feet, inches, and pounds) with the unit toggle - and the calculator returns your BMI along with the World Health Organization category it falls into: underweight below 18.5, normal weight from 18.5 to 24.9, overweight from 25 to 29.9, and obese at 30 and above.
BMI is calculated as weight in kilograms divided by height in metres squared; the imperial inputs are converted to metric first, so both unit systems give the same result. Everything runs in your browser and nothing is sent to a server. Keep in mind that BMI is a population-level guide, not a diagnosis - it does not distinguish muscle from fat or account for age, sex, or body composition, so treat it as a starting point rather than the whole picture.
Example. Someone 175 cm tall weighing 70 kg has a BMI of 70 / 1.75^2 = 22.9, which sits in the normal-weight range. In imperial, that is roughly 5 ft 9 in and 154 lb, and the calculator returns the same 22.9.
FAQ
How is BMI calculated?
BMI equals your weight in kilograms divided by the square of your height in metres (kg / m^2). For imperial inputs the tool converts feet, inches, and pounds to metric first, so you get an identical result either way.
What are the BMI categories?
Using the WHO ranges for adults: underweight is below 18.5, normal weight is 18.5 to 24.9, overweight is 25 to 29.9, and obese is 30 or higher. The tool shows which band your BMI lands in as you type.
Is BMI accurate for everyone?
BMI is a rough screening tool, not a diagnosis. It does not separate muscle from fat and does not account for age, sex, ethnicity, or body shape, so very muscular people can read as "overweight" while the figure may understate body fat in others. Use it as a general guide and talk to a healthcare professional for anything specific.
Is my height and weight sent anywhere?
No. The calculation happens entirely in your browser. Nothing you enter is uploaded, logged, or stored on a server.