Body Mass Index Calculator
Work out a BMI from weight and height, see which band it falls in, and see the weight range that band corresponds to at your height.
Runs entirely in your browser — nothing is uploaded
In kilograms.
In centimetres.
Body mass index
22.9
Healthy weight(18.5 to 24.9)
At this height, 18.5 to 24.9 corresponds to 56.7–76.3 kg.
BMI is a ratio of weight to height and nothing more. It does not distinguish muscle from fat, and it is a population screening measure rather than a diagnosis of anything. Read it as one number among several.
What BMI actually measures
Weight divided by height squared. That is the entire formula, and it is worth knowing because it explains both why BMI is useful and why it is limited.
It was devised in the 1830s by a Belgian statistician studying populations, not patients. It does what it was built for — describing groups — and it has been doing a job it was never designed for ever since.
It cannot tell muscle from fat
The formula has no way to know what the weight is made of. A muscular athlete and a sedentary person of the same height and weight get the same number, and one of them is being described badly.
It also takes no account of where weight is carried, which matters medically, and it is known to fit some ethnic groups better than others — several health bodies use lower thresholds for South Asian populations for exactly this reason.
Read it as one number among several
BMI is a screening measure. It is a cheap, fast way to decide whether a longer conversation is worth having, and it is not a diagnosis of anything on its own.
This tool shows the band and also the weight range that band corresponds to at your height, because a range is more useful than a verdict. Nothing here is medical advice, and a number that concerns you is a reason to speak to a doctor rather than to a website.
Nothing is sent anywhere
Every figure on this page is worked out in your own browser. No request is made, nothing is stored between visits, and the page keeps working with the connection switched off.
Frequently asked questions
What are the BMI categories?
Below 18.5 is underweight, 18.5 to 24.9 is the healthy range, 25.0 to 29.9 is overweight, and 30.0 and above is obese. These are the World Health Organization thresholds for adults.
Does this work for children?
No. Children and teenagers are assessed against age and sex percentile charts rather than fixed thresholds, because the healthy ratio changes throughout growth. Using adult bands for a child gives a meaningless answer.
Why does my BMI say overweight when I am fit?
Because muscle is denser than fat and the formula cannot see the difference. This is the single best known limitation of BMI, and it is why it is a screening tool rather than a measurement of health.
Is my weight or height stored?
No. Both are typed into this tab, used for the sum, and gone when the page closes. Nothing is transmitted and there is no account.