About the BMI Calculator
Check your Body Mass Index in seconds. Enter your height and weight and get your BMI, its CDC weight category, and the healthy weight range for your height — in pounds or kilograms.
Height and weight stay on your device. Nothing is uploaded, and no result is stored — which is how a health figure ought to be handled.
Results are estimates for general information only and are not medical advice. Talk to a healthcare professional before making significant changes to your diet or exercise.
How to use it
- Choose metric or imperial units.
- Enter your height and weight.
- Read your BMI and the category it falls in.
What BMI does and does not measure
BMI is weight divided by height squared. It is a population-level screening figure, designed to flag trends across large groups.
It cannot distinguish muscle from fat and takes no account of where fat is carried. A muscular athlete and a sedentary person of the same height and weight get identical scores despite very different health profiles.
A worked example
Metric: 78 kg at 1.75 m → 78 ÷ (1.75 × 1.75) = 25.5
Imperial: 172 lb at 5'9" → (703 × 172) ÷ (69 × 69) = 25.4
Both land just over the 25.0 line into 'overweight'. Both are also within a rounding error of 'normal', which is a good illustration of why a single decimal point should not be treated as a diagnosis.
Common mistakes
- Reading BMI as a body-fat percentage. It is not one, and it never was.
- Applying adult categories to children, who need age- and sex-specific percentile charts instead.
- Ignoring waist measurement, which is often a better indicator of metabolic risk than BMI alone.
Questions people ask
What are the standard categories?
Under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30 and above obese. These thresholds are for adults and are known to fit some ethnic groups poorly.
Is BMI accurate for athletes?
Often not. Muscle is dense, so well-trained athletes frequently score as overweight while carrying very little fat.
What should I use instead?
Waist circumference, waist-to-height ratio and body-fat percentage each add information. For anything that matters, talk to a clinician rather than a calculator.