BMI screens adults, it is not a diagnosis — see a doctor for advice.
What the BMI Calculator does
This tool turns your weight and height into a Body Mass Index score, the weight category it falls into, a visual scale showing exactly where you land, and the healthy weight range for your height. Work in metric (kg, cm) or imperial (lb, ft/in) with a single toggle — no converting by hand — so the numbers you already know just work. BMI is the same figure doctors, gyms and insurers use as a starting point, and this makes it fast to read and act on.
The whole calculation happens on your device. Your weight and height are never sent anywhere.
How to use it
- Pick Metric or Imperial with the units toggle.
- Enter your weight and height in those units.
- Your BMI, category and position on the scale update instantly as you type.
- Read the healthy weight range for your height, plus how much to lose or gain to reach a normal BMI.
What the result tells you
- Your BMI and category — Underweight, Normal, Overweight or Obese, using the standard WHO adult cutoffs (18.5 / 25 / 30).
- The visual scale — a coloured bar with a marker so you can see at a glance how close you are to the next band.
- Healthy weight range — the weights that give a normal BMI for your exact height, in your units, with a plain “lose/gain about X” pointer when you are outside it.
A note on BMI
BMI is a screening figure, not a full health verdict. It does not know the difference between muscle and fat, so very athletic builds often read higher than expected, and it is meant for adults rather than children. Treat it as a rough guide and get a professional opinion for anything important.
Frequently asked questions
- How is BMI calculated in this tool?
- It uses the standard formula: weight divided by height squared. In metric that is kilograms over metres squared; in imperial the tool converts pounds and feet/inches to metric first, so both give the same result, rounded to one decimal place.
- Can I use pounds and feet/inches?
- Yes. Switch the units toggle to Imperial and enter weight in pounds and height in feet and inches. Switch to Metric for kilograms and centimetres. You never have to convert by hand.
- What do the BMI categories mean?
- The result is sorted into four bands based on common World Health Organization cutoffs: under 18.5 is Underweight, 18.5 to 24.9 is Normal, 25 to 29.9 is Overweight, and 30 or above is Obese. These ranges are for adults.
- What is the healthy weight range it shows?
- It is the weight range that would put your BMI between 18.5 and 24.9 for your exact height, shown in your chosen units. If you are outside it, the tool also tells you roughly how much to lose or gain to reach a normal BMI.
- Is BMI an accurate measure of health?
- BMI is a quick screening number, not a diagnosis. It does not separate muscle from fat, so athletes and very muscular people can read high. Use it as general guidance and talk to a doctor for a real assessment.
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Last updated: July 7, 2026