BMI Calculator
Last updated: 2026-06-25
BMI (body mass index) divides your weight in kilograms by the square of your height in meters to gauge whether your weight is healthy.
The formula is BMI = weight(kg) ÷ (height(m) × height(m)). A BMI of 18.5–24.9 is considered normal under WHO standards.
Calculate BMI from your height and weight
Your BMI (body mass index)
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WHO category: –
Asian-Pacific category: –
- Ideal weight (BMI 22)
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- Healthy weight range
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Please enter a valid height and weight.
How to use it
- Enter height — enter your height in centimeters (cm). Example: 170. (170 cm ≈ 5 ft 7 in.)
- Enter weight — enter your weight in kilograms (kg). Example: 65. (65 kg ≈ 143 lb.)
- View result — press Calculate and your BMI value and weight category appear instantly.
What is BMI?
BMI (Body Mass Index) is the most widely used screening number for estimating whether a person's weight is healthy, using only height and weight. It is quick and free to calculate, which is why clinics and health checks use it as a first-line screen. The BMI formula is:
BMI = weight(kg) ÷ ( height(m) × height(m) )
Example: height 170 cm (=1.7 m), weight 65 kg → 65 ÷ (1.7 × 1.7) = 22.5
BMI weight categories (WHO and Asian-Pacific)
BMI thresholds differ by region. The WHO international standard is shown below. For Asian populations, lower cut-offs are often used because, at the same BMI, body fat and metabolic risk tend to be higher. This calculator reports both the WHO standard category and the Asian-Pacific category.
| Category | BMI range (kg/m²) |
|---|---|
| Underweight | Below 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese class I | 30.0 – 34.9 |
| Obese class II | 35.0 – 39.9 |
| Obese class III (severe) | 40.0 and above |
| Category | BMI range (kg/m²) |
|---|---|
| Underweight | Below 18.5 |
| Normal | 18.5 – 22.9 |
| Overweight (pre-obese) | 23.0 – 24.9 |
| Obese class I | 25.0 – 29.9 |
| Obese class II | 30.0 – 34.9 |
| Obese class III (severe) | 35.0 and above |
Things to keep in mind when reading BMI
- BMI cannot tell muscle from fat. A very muscular athlete may have a high BMI without being over-fat.
- Conversely, "skinny fat" (normal-weight obesity) — low muscle, high fat — can carry health risk even with a normal BMI.
- For abdominal fat, also check waist circumference (roughly 102 cm / 40 in for men, 88 cm / 35 in for women suggests high risk).
- Children, teens, pregnant women and older adults should not be assessed with standard adult BMI cut-offs.
For a deeper read, see our guide to BMI range, limits and how to read it correctly.
Frequently asked questions (FAQ)
How is BMI calculated?
BMI is your weight in kilograms divided by the square of your height in meters. For example, at 170 cm (1.7 m) and 65 kg, BMI = 65 ÷ (1.7 × 1.7) = 22.5.
What is a normal BMI range?
Under WHO standards, a BMI of 18.5–24.9 is normal, 25 and above is overweight, and 30 and above is obese. For Asian-Pacific populations, lower cut-offs of 23 (overweight) and 25 (obese) are often used. This tool reports both.
How do WHO and Asian-Pacific BMI standards differ?
The international WHO standard treats BMI 25+ as overweight and 30+ as obese. The Asian-Pacific standard uses lower thresholds (23+ overweight, 25+ obese) because, at the same BMI, Asian populations tend to have higher body fat and metabolic risk.
Can my BMI be normal but I'm still over-fat?
Yes. BMI cannot distinguish muscle from fat, so someone with low muscle and high body fat ("skinny fat" or normal-weight obesity) can have a normal BMI but a high body fat percentage. Measuring body fat percentage is recommended for a more accurate picture.
Can children or pregnant women use this BMI calculator?
This calculator is for adults. Children and teens should use age-specific BMI percentiles, and pregnancy involves normal weight gain so standard BMI categories do not apply. Those groups should consult a healthcare professional.
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Last updated: 2026-06-25