What is a normal BMI?

According to the WHO, a BMI between 18.5 and 24.9 is considered normal weight. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese.

How is BMI calculated?

BMI = weight (kg) ÷ height² (m²). In imperial units: BMI = 703 × weight (lbs) ÷ height² (inches²).

Does BMI account for muscle mass?

No. BMI does not distinguish between muscle and fat. Athletes may have a high BMI despite low body fat. It is a screening tool, not a diagnostic measure.

⚖️ BMI Calculator

Calculate your Body Mass Index instantly. Get your BMI category, healthy weight range, and ideal body weight — in metric or imperial units.

Metric & Imperial Healthy Range Ideal Weight

Height (cm)

Weight (kg)

FAQ

What BMI range is considered healthy?

The WHO classifies BMI as: Underweight < 18.5, Normal weight 18.5–24.9, Overweight 25–29.9, Obese class I 30–34.9, Obese class II 35–39.9, Obese class III ≥ 40.

Is BMI accurate for athletes and muscular people?

BMI is a rough screening tool. Athletes and people with high muscle mass may show a high BMI despite low body fat, because muscle is denser than fat. Similarly, older adults may have a "normal" BMI but high body fat due to muscle loss.

Does BMI apply to children?

Standard adult BMI cutoffs do not apply to children and teens. For ages 2–19, BMI-for-age percentiles (using CDC or WHO growth charts) are used instead. This tool is designed for adults only.

What is the Ponderal Index?

The Ponderal Index (PI) is an alternative body composition measure: weight (kg) ÷ height³ (m³). It is sometimes considered more reliable for very tall or very short individuals where BMI can be misleading. Normal PI range is approximately 11–14 kg/m³.