Free tool
BMI calculator
Body Mass Index compares your weight to your height. It is a crude screening number rather than a verdict on your health — but it is quick, and it gives you a healthy weight range to aim at.
Read it with caution
BMI does not know the difference between muscle and fat. A lean, heavily trained person can land in the “overweight” band while carrying very little fat, and someone within the healthy band can carry a lot.
It also ignores where fat sits, which matters — waist measurement is a better single predictor of metabolic risk than BMI is.
What BMI is genuinely useful for is a rough starting range. If you want a target weight, the healthy range shown here is a reasonable place to begin.
Categories
What the bands mean.
These are the standard World Health Organization cut-offs. Some health bodies use lower thresholds for South Asian, Chinese and Japanese populations, where metabolic risk tends to rise at a lower BMI — around 23 rather than 25.
| BMI | Category | Note |
|---|---|---|
| Under 18.5 | Underweight | Worth discussing with a doctor |
| 18.5 – 24.9 | Healthy weight | The range this calculator targets |
| 25 – 29.9 | Overweight | Often muscle in trained people |
| 30 – 34.9 | Obese, class I | |
| 35 – 39.9 | Obese, class II | |
| 40 and over | Obese, class III |
Frequently asked questions
Is BMI accurate for athletes?
Often not. Muscle is denser than fat, so trained people frequently score as overweight while carrying low body fat. If you lift seriously, use body fat percentage and waist measurement instead.
Is BMI different for Indian or South Asian people?
Several health bodies use lower thresholds for South Asian populations — overweight from about 23 and obese from about 27 — because metabolic risk tends to appear at a lower BMI. This calculator shows the standard WHO bands; adjust your reading accordingly.
What should I use instead of BMI?
Waist circumference, waist-to-height ratio (keep your waist under half your height), body fat percentage, and simply how your clothes fit over months. Any of these tells you more than BMI alone.
Does BMI apply to children or pregnancy?
No. Children are assessed on age-and-sex percentile charts, and BMI is not meaningful during pregnancy. Speak to a doctor in both cases.
Next step
A number is not a plan.
BetterCal tracks what you actually eat, in one sentence a meal. Free to start on iPhone and Android.
