BMI Calculator
Check if your weight is healthy for your height.
BMI (Body Mass Index) is a number calculated from your height and weight that estimates whether you are in a healthy weight range. This BMI calculator works it out in metric or US units and shows your BMI, its category (underweight, normal, overweight or obese) and the healthy weight range for your height. Runs fully in your browser — nothing is uploaded.
How to use BMI Calculator
Choose your units
Switch the free online BMI calculator between metric (kg/cm) and US (lb/ft) units so you can enter your weight and height in whichever system you prefer.
Enter your weight
Type your current body weight into the weight field — the BMI calculator uses it as the numerator in the Body Mass Index formula to gauge whether your weight is healthy.
Enter your height
Add your height in centimetres, or feet and inches, and the tool instantly squares it to compute BMI = weight (kg) ÷ height (m)².
Read your BMI
Your Body Mass Index appears at once on a colour-coded WHO gauge, with the matching category — underweight, normal, overweight or obese — highlighted instantly.
Check the healthy range
See the healthy weight range for your height and exactly how many kilograms you would need to gain or lose to land inside the normal BMI band.
Share your result
Copy the share link to save or send your BMI result — everything is calculated privately in your browser, so no weight or height data is ever uploaded.
Frequently asked questions
What is a healthy BMI?
A BMI between 18.5 and 24.9 is considered the healthy range for most adults. Below 18.5 is underweight; 25–29.9 is overweight; 30 and above is obese.
Is BMI accurate for athletes?
Not always. BMI only uses height and weight, so it can over-estimate body fat in very muscular people and under-estimate it in those with low muscle mass. Use it alongside other measures like waist size or body-fat percentage.
Does BMI work the same for children?
No. For children and teens, BMI is interpreted against age- and sex-specific percentile charts, not the fixed adult bands shown here. This tool is intended for adults.
How do I calculate my BMI?
Enter your weight and height in this free BMI calculator and it works out your Body Mass Index using BMI = weight (kg) ÷ height (m)². You can switch between metric (kg/cm) and US (lb/ft) units, and it shows your category on a WHO band gauge instantly.
Is BMI different for men and women?
No — the BMI formula and the adult healthy range of 18.5–24.9 are the same for men and women. Because BMI ignores body composition, men (who often carry more muscle) and very athletic people may read higher than their actual body fat suggests.
What is a normal BMI for my age?
For adults, the healthy BMI range (18.5–24.9) is the same across ages — it doesn't change by age band. Note that BMI can read higher in older adults with less muscle and lower in very muscular people, so use it as a general guide alongside waist size.
How do I lower my BMI?
BMI drops as your weight decreases for the same height, so a gradual calorie deficit and regular activity lower it over time. Use the Calorie Calculator to set a safe daily target, and re-check your BMI here as your weight changes.
Is my data sent anywhere?
No. Everything is calculated in your browser with JavaScript — nothing you enter is uploaded.
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