BMI Calculator
100% in your browser — nothing is uploadedYour BMI
25.1
Overweight
BMI is a screening measure, not a diagnosis — it doesn't distinguish muscle from fat or account for age and body composition.
Body Mass Index is weight in kilograms divided by height in meters squared — a screening number used by clinicians and insurers to sort weight into standard ranges. Enter your height and weight in either US or metric units and your BMI appears instantly, alongside the WHO category ranges so you can see the thresholds, not just your number.
Treat BMI as a starting point, not a verdict. It can't tell muscle from fat: athletes routinely read 'overweight' while carrying little body fat, and the ranges fit older adults and some ethnic groups imperfectly. If your number sits near a boundary, measurements like waist circumference and a conversation with a clinician say far more.
How to use the bmi calculator
- Choose US or metric units.
- Enter your weight and height.
- Read your BMI and the category ranges next to it.
Frequently asked questions
What is a healthy BMI?
The WHO ranges used by this calculator: under 18.5 is underweight, 18.5–24.9 is the healthy-weight range, 25–29.9 is overweight, and 30+ is classed as obesity. These are population screening bands, not individual diagnoses.
Why does BMI mislabel athletes?
BMI only knows mass and height. Muscle is denser than fat, so a muscular person carries more mass at the same height and reads higher — the formula can't see body composition.
Is my health data stored?
No. The calculation runs in your browser; your height and weight are never transmitted or saved.