BMI Calculator
Body mass index with WHO categories and your healthy weight range — metric or imperial.
Enter your height and weight — in centimeters and kilograms or feet, inches, and pounds — and see your body mass index instantly, plotted on a color-coded scale with the WHO categories: underweight, normal, overweight, and obese. The calculator also shows the healthy weight range for your exact height, so you know what "normal BMI" means in actual kilograms or pounds.
BMI is the screening measure used by the WHO, physicians, and insurers because it needs only two numbers. It is a useful starting point for tracking trends over time, but it cannot see body composition — muscular people often score "overweight" with low body fat. Treat the result as information, not a diagnosis.
How to calculate your BMI
- 1
Choose metric (cm, kg) or imperial (ft + in, lbs) units.
- 2
Enter your height and weight — BMI appears instantly, to one decimal.
- 3
Check your WHO category on the scale and the healthy weight range for your height.
Why use Nofolo’s bmi calculator?
Metric and imperial
Switch between cm/kg and ft+in/lbs — the calculation updates instantly either way.
WHO categories
Underweight, normal, overweight, and obese ranges exactly as defined by the World Health Organization.
Visual BMI scale
A color-coded bar shows precisely where your value sits within and between categories.
Healthy weight range
The weight span that corresponds to a normal BMI for your height, in your chosen units.
Live results
BMI recalculates on every keystroke — no submit button.
Private
Height and weight never leave your browser. Nothing is stored or transmitted.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². In imperial units the equivalent formula is 703 × weight (lb) ÷ height (in)². A BMI of 22 means your weight is 22 times your height in meters squared.
What is a healthy BMI?
The WHO defines 18.5–24.9 as the normal range for adults, below 18.5 as underweight, 25–29.9 as overweight, and 30 and above as obese. The calculator converts that range into actual weight for your height.
Is BMI accurate for everyone?
No — and that is by design. BMI is a population-level screening tool. It over-reads athletes and muscular builds, under-reads people with low muscle mass, and uses the same cutoffs for all adults under 65. Waist measurement and body-fat testing add the missing context.
Does BMI work for children?
Not with these adult cutoffs. Children and teens are assessed with age- and sex-specific BMI percentile charts — use a pediatric tool or ask a pediatrician.
Should I make health decisions based on my BMI?
Use it as a conversation starter, not a verdict. BMI is one screening signal among many — a doctor will consider waist circumference, blood work, history, and lifestyle before drawing any conclusion.
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