Enter your height and weight to get your body mass index, its WHO category and the healthy weight range for your height. Below the calculator: how to calculate BMI by hand, a BMI table by height and what BMI cannot tell you.
Reviewed by João Freitas · Formula: weight / height² (WHO adult categories)
BMI (body mass index) is your weight divided by the square of your height. It takes ten seconds with a calculator on your phone:
Worked example (metric): 70 kg and 175 cm. Convert the height to metres (1.75), square it (1.75 × 1.75 = 3.0625) and divide: 70 / 3.0625 = 22.9, inside the healthy range.
Worked example (imperial): 154 lb and 5 ft 9 in (69 in). Square the height (69 × 69 = 4,761), then 703 × 154 / 4,761 = 22.7.
BMI Prime is your BMI divided by 25, the top of the healthy range. A value of 1.00 sits exactly at the upper limit; 0.90 is 10% below it.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25 to 29.9 | Overweight |
| 30 to 34.9 | Obesity (class I) |
| 35 to 39.9 | Obesity (class II) |
| 40 or more | Obesity (class III) |
The weight ranges that match each BMI category at common heights: healthy is a BMI of 18.5 to 24.9, overweight 25 to 29.9 and obese 30 or more (adults, rounded to the nearest kilogram).
| Height | Healthy | Overweight | Obese |
|---|---|---|---|
| 150 cm | 42-56 kg | 56-68 kg | 68 kg+ |
| 155 cm | 44-60 kg | 60-72 kg | 72 kg+ |
| 160 cm | 47-64 kg | 64-77 kg | 77 kg+ |
| 165 cm | 50-68 kg | 68-82 kg | 82 kg+ |
| 170 cm | 53-72 kg | 72-87 kg | 87 kg+ |
| 175 cm | 57-76 kg | 77-92 kg | 92 kg+ |
| 180 cm | 60-81 kg | 81-97 kg | 97 kg+ |
| 185 cm | 63-85 kg | 86-103 kg | 103 kg+ |
| 190 cm | 67-90 kg | 90-108 kg | 108 kg+ |
| 195 cm | 70-95 kg | 95-114 kg | 114 kg+ |
BMI only knows your height and weight, so it cannot separate muscle from fat or say where the fat sits. A muscular person can read as overweight with little body fat, and someone with little muscle can read as healthy while carrying too much. The WHO also notes that for many Asian populations health risk starts at lower values (around 23 instead of 25). For children and teenagers BMI is read against age and sex percentiles instead of these adult categories. If your number surprises you, measure your body fat and your waist as well: see BMI vs body fat percentage.
Divide your weight in kilograms by your height in metres squared. For example, 70 kg at 1.75 m is 70 / (1.75 x 1.75) = 22.9. In imperial units, multiply your weight in pounds by 703 and divide by your height in inches squared.
For adults, the World Health Organization defines 18.5 to 24.9 as the healthy range. Below 18.5 is underweight, 25 to 29.9 is overweight and 30 or more is obesity.
It is a good screening tool for groups and a rough one for individuals. BMI cannot tell muscle from fat, so muscular people can read as overweight and people with little muscle can read as healthy while carrying a lot of fat. A body fat estimate and your waist size add the missing context.
Not in the same way. For children and teenagers BMI is read against age and sex percentiles, not adult cut-offs. In older adults and in athletes the adult ranges are less reliable because of changes in muscle mass, so pair BMI with a body fat measurement.
Estimate your body fat percentage with a tape measure or calipers, the number BMI cannot see.
When BMI is the right tool, when it misleads, and how to read it together with body fat and waist size.
Turn a weight goal into daily calories and macros, based on your height, weight and activity.
Disclaimer: educational purposes only. Not medical advice. If you have a medical condition, talk to a qualified professional.