BMI categories for adults
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25 to 29.9 | Overweight |
| 30 and above | Obese |
How BMI is calculated
BMI is your weight in kilograms divided by your height in metres squared: BMI = kg ÷ m². Someone who is 1.70 m tall and weighs 70 kg has a BMI of 70 ÷ (1.70 × 1.70) = 24.2. In US units, use 703 × lb ÷ in².
Is BMI the same for women and men?
Yes. Adult BMI uses the same formula and categories for both. But at the same BMI, women usually carry more body fat than men, and muscular people can show a high BMI without extra fat. Waist size is a useful second check. A waist over half your height can point to higher health risk.
BMI for children and teens
This calculator is for adults. For ages 2 to 19, BMI is compared with growth charts for the same age and sex, and the result is a percentile. Use a children’s BMI tool from your health service or ask your doctor.
BMI Calculator FAQs
What is a healthy BMI?
For most adults, 18.5 to 24.9 is considered a healthy range. Some groups use slightly lower cut-offs.
How do I calculate BMI in pounds and inches?
Multiply your weight in pounds by 703, then divide by your height in inches squared. For 154 lb and 67 inches: 703 × 154 ÷ 4,489 = 24.1.
Does BMI work for athletes?
Not very well. Muscle is heavier than fat, so athletes often get a high BMI even with low body fat.
Does age change BMI for adults?
The adult categories are the same at every age from 18. Some doctors are less strict with older adults, where a slightly higher BMI may be fine.
Is my data saved?
No. The calculation happens in your browser, and nothing is sent or stored.