StatusQueen's BMI Calculator turns your height and weight into a single, internationally-recognised number — Body Mass Index — and places it on the WHO scale so you can see where it sits. The math is the same one used in every clinic; the presentation is meant to feel like a calm reading rather than a judgement.
How BMI is calculated
Body Mass Index is a ratio: your weight relative to your height. In metric, it's weight (kg) ÷ height (m)². In imperial, it's (weight (lb) ÷ height (in)²) × 703. The same person enters the same number in either system — the formula simply unit-converts.
WHO categories (adults 20+)
- Below 18.5 — Underweight
- 18.5 – 24.9 — Normal / healthy range
- 25.0 – 29.9 — Overweight
- 30.0 – 34.9 — Obese (class I)
- 35.0 – 39.9 — Obese (class II)
- 40 and above — Obese (class III)
What BMI does not measure
BMI is a screening tool, not a diagnosis. A few things it cannot see:
- Muscle vs fat — athletes often read as "overweight" because muscle is denser than fat. A weightlifter and a sedentary person of identical BMI are physiologically very different.
- Body composition — bone density, hydration, and frame size all shift the number.
- Fat distribution — abdominal fat carries different health implications than peripheral fat. BMI sees only the total.
- Age and ethnicity — research suggests the same BMI carries different risk across age groups and populations. Some health bodies use adjusted thresholds for South Asian, Asian and Pacific Islander adults.
How to use the result well
A useful way to read your BMI: it's a starting point for a conversation, not a final score. If your BMI lands outside the normal range and you have other signals — energy, sleep, blood markers, how clothes fit, how you move — taken together they form a fuller picture than the number alone. Share both with your doctor.
Privacy
Every calculation runs entirely in your browser. Your height and weight never reach our servers — no logging, no analytics on the inputs, no sign-up. Close the tab and the numbers are gone. For details, see our Privacy Policy.
Frequently Asked Questions
Is BMI an accurate measure of health?
BMI is useful as a quick screening number, but on its own it is incomplete. It cannot tell muscle from fat, and it does not see body composition, fat distribution, or many of the factors that actually shape long-term health. Read it as one input, not as a verdict.
Does this calculator work for children?
The adult WHO categories shown here apply to people aged 20 and over. For children and teenagers, BMI is interpreted using age- and sex-specific percentile charts — use a paediatric BMI tool or ask your child's doctor for those readings.
Why do my metric and imperial results match?
They should — both formulas describe the same physical quantity in different units. If they differ noticeably, double-check that the inputs are entered correctly: imperial expects feet and inches in two boxes, weight in pounds; metric expects centimetres and kilograms.
Are my measurements stored anywhere?
No. The math happens entirely in your browser. Your height and weight never reach our servers.
What's a "healthy" weight range for my height?
The calculator reports the weight range that produces a BMI between 18.5 and 24.9 for the height you entered. That's the WHO-defined normal band — for many people, but not all, this range corresponds to a comfortable, sustainable body composition.