Body Mass Index (BMI) is a numerical value calculated from your weight and height. It is widely used by healthcare professionals as a screening tool to assess whether a person has a healthy body weight for their height. The BMI formula was developed by Belgian mathematician Adolphe Quetelet in the 1830s and was adopted by the World Health Organization (WHO) as a global standard.
While BMI is a useful first indicator, it does not directly measure body fat. A muscular athlete may have a high BMI without excess fat, while an older person with low muscle mass may have a normal BMI but unhealthy body composition.
Select your preferred unit system: Metric (kg and cm) or Imperial (lbs and feet/inches)
Enter your weight in the first field
Enter your height in the second field (imperial users: enter feet and inches separately)
Click Calculate BMI to see your result, category, and the visual gauge
Healthy Weight Ranges by Height
Approximate healthy weight (BMI 18.5–24.9) by height:
Height (cm)
Height (ft/in)
Min Weight (kg)
Max Weight (kg)
Frequently Asked Questions — BMI
► What is a healthy BMI?
A healthy BMI is between 18.5 and 24.9. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese, according to the World Health Organization (WHO).
► How is BMI calculated?
BMI = weight in kilograms ÷ (height in meters)². In imperial: BMI = 703 × weight (lbs) ÷ height² (inches). A 70 kg person who is 1.75 m tall has a BMI of 70 ÷ 3.0625 = 22.9.
► Is BMI accurate for everyone?
BMI is a useful population-level screening tool but has limitations. Athletes with high muscle mass may appear overweight by BMI despite low body fat. Older adults may have normal BMI but excess body fat. It does not account for fat distribution (e.g., abdominal fat). Always consult a healthcare professional for a complete assessment.
► What BMI is considered overweight?
A BMI of 25.0 to 29.9 is considered overweight. A BMI of 30 or above is classified as obese. These thresholds apply to most adults, though some health organizations use different cutpoints for certain ethnic groups (e.g., Asians at 23).
► What is the ideal BMI for men and women?
The WHO uses the same BMI scale for men and women: 18.5–24.9 is healthy for both. However, women naturally have a higher body fat percentage at the same BMI as men. For detailed body composition analysis, consider a DEXA scan or body fat percentage measurement.