BMI Calculator — Metric & Imperial
Check your body mass index in seconds, see your WHO category on a color scale, and get the healthy weight range for your height. Runs entirely in your browser.
Your BMI
24.2
Category
Normal
Healthy weight range for your height (BMI 18.5–24.9):
53.5 – 72.0 kg
BMI is a screening tool, not medical advice. It does not account for muscle mass, age, or body composition — talk to a healthcare professional about your individual health.
Want to understand what your BMI does — and does not — say about your health? Read our plain-English BMI guide
Frequently Asked Questions
How is BMI calculated?▼
BMI is weight in kilograms divided by height in meters squared (kg/m²). For imperial units the same formula is applied after converting: pounds × 0.4536 for weight and total inches × 0.0254 for height. A 70 kg person who is 1.70 m tall has a BMI of 70 ÷ (1.70 × 1.70) = 24.2.
What are the WHO BMI categories?▼
The World Health Organization defines four adult ranges: Underweight below 18.5, Normal weight 18.5–24.9, Overweight 25–29.9, and Obese 30 and above. The colored scale above shows exactly where your value falls.
Is BMI accurate for everyone?▼
No. BMI is a population-level screening measure, not a diagnosis. It cannot distinguish muscle from fat, so athletes often read "overweight" while being lean, and it is less reliable for older adults, pregnant women, and children (who use age-adjusted percentile charts instead).
How is the healthy weight range worked out?▼
We invert the BMI formula for your height: the low end is 18.5 × height² and the high end is 24.9 × height² (height in meters), converted to pounds if you use imperial units. It is the weight span that would put your BMI in the WHO "Normal" band.
Is my height and weight data stored anywhere?▼
No. The calculation runs entirely in your browser with no server calls — nothing you type is uploaded, logged, or saved, and the tool keeps working offline once the page has loaded.