🩺 BMI Calculator
BMI = weight (kg) ÷ height (m)² — a 70 kg person at 175 cm has a BMI of 22.9. Enter your values below — results update instantly, entirely on your device.
70 ÷ 1.75² — WHO adult scale
How the bmi calculator works
BMI = weight in kilograms ÷ (height in meters)². WHO adult ranges: under 18.5 underweight · 18.5–24.9 normal · 25–29.9 overweight · 30+ obesity.
Example: 70 kg at 175 cm → 70 ÷ 1.75² = 22.9 (normal range).
BMI is a population screening measure, not a diagnosis: it cannot distinguish muscle from fat, so athletes often read "overweight" while lean-mass poor individuals can read "normal". Health data is exactly the kind of input you shouldn’t hand to random web servers — this calculator never transmits yours anywhere.
Frequently asked questions
What is a healthy BMI?
For adults, the WHO defines the normal range as 18.5–24.9. The calculator also shows the weight range that corresponds to normal BMI at your height.
Is BMI accurate for athletes?
Not particularly — muscle is denser than fat, so muscular people often score 25+ while being very lean. Waist measurements and body-fat percentage are better signals in that case.
Does the formula differ for imperial units?
The imperial form is weight (lb) ÷ height (in)² × 703. Convert first with the lbs-to-kg tool if needed; both routes give the same BMI.
Is this bmi calculator accurate and private?
Yes. It uses the standard published formula, shows its working under every result, and computes locally in your browser — your inputs are never sent to a server, and the page works offline.