Health
BMI Calculator
Body mass index from height and weight, metric or imperial, with your WHO category and healthy weight range.
Result
Updates as you typeYour body mass index
26.1 kg/m²
- Category (WHO)
- Overweight
- Healthy weight range for your height
- 56.7 – 76.5 kg
- Distance from the normal range
- 3.5 kg over
How it's calculated
Body mass index (BMI) is your weight divided by the square of your height. The World Health Organization uses it to classify underweight, overweight and obesity in adults.
The result is rounded to one decimal place in a way that never changes the category. BMI does not measure body fat directly; it is a screening indicator.
Worked example
An adult who is 175 cm (5 ft 9 in) tall and weighs 80 kg (176 lb):
- Height squared: 1.75 × 1.75 = 3.0625 m²
- BMI: 80 / 3.0625 = 26.1 kg/m² → Overweight
- Healthy weight range: 56.7 – 76.5 kg (125 – 169 lb) — 3.5 kg to lose to reach it
BMI tables
WHO BMI classification (adults)
| BMI (kg/m²) | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity class I |
| 35.0 – 39.9 | Obesity class II |
| 40.0 and above | Obesity class III |
Healthy weight range by height
| Height | Healthy weight | In pounds |
|---|---|---|
| Height: 150 cm (4 ft 11 in) | Healthy weight41.7 – 56.2 kg | In pounds92 – 124 lb |
| Height: 155 cm (5 ft 1 in) | Healthy weight44.5 – 60.0 kg | In pounds98 – 132 lb |
| Height: 160 cm (5 ft 3 in) | Healthy weight47.4 – 63.9 kg | In pounds104 – 141 lb |
| Height: 165 cm (5 ft 5 in) | Healthy weight50.4 – 68.0 kg | In pounds111 – 150 lb |
| Height: 170 cm (5 ft 7 in) | Healthy weight53.5 – 72.2 kg | In pounds118 – 159 lb |
| Height: 175 cm (5 ft 9 in) | Healthy weight56.7 – 76.5 kg | In pounds125 – 169 lb |
| Height: 180 cm (5 ft 11 in) | Healthy weight60.0 – 80.9 kg | In pounds132 – 178 lb |
| Height: 185 cm (6 ft 1 in) | Healthy weight63.4 – 85.5 kg | In pounds140 – 188 lb |
| Height: 190 cm (6 ft 3 in) | Healthy weight66.8 – 90.2 kg | In pounds147 – 199 lb |
| Height: 195 cm (6 ft 5 in) | Healthy weight70.4 – 95.0 kg | In pounds155 – 209 lb |
| Height: 200 cm (6 ft 7 in) | Healthy weight74.0 – 99.9 kg | In pounds163 – 220 lb |
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) / height (m)². For example, 80 kg at 1.75 m gives 80 / (1.75 × 1.75) = 26.1 kg/m², which is in the “Overweight” category. With pounds and inches: BMI = weight (lb) × 703 / height (in)².
What is a normal BMI?
The World Health Organization classes a BMI of 18.5 – 24.9 as normal weight for adults. 25 and above is overweight, 30 and above is obesity, and below 18.5 is underweight.
What is a healthy weight for my height?
The healthy weight range is every weight that keeps your BMI between 18.5 – 24.9 (below 25): height² × 18.5 to height² × 25. For 170 cm that is 53.5 – 72.2 kg (about 117.95 – 159.17 lb). The calculator shows the range for the height you enter.
Does BMI apply to children and teenagers?
No. This classification is for adults aged 18 and over. For children and adolescents (5–19), the WHO growth reference uses age- and sex-specific BMI percentiles; ask a paediatrician.
Is BMI always accurate?
BMI does not distinguish fat from muscle. It can read high in athletes with a lot of muscle and low in older adults who have lost muscle, and it is not used in pregnancy. It is a screening measure: combine it with waist circumference and talk to a doctor about health decisions.
Is BMI the same as ideal weight?
No. BMI relates your current weight to your height; ideal weight is an estimate of a target weight for your height. For height- and sex-based formulas, use the Ideal Weight Calculator.
Sources
BMI is a screening indicator, not a diagnosis. Muscle mass, age, sex and ethnicity affect what a given BMI means. Talk to a doctor about decisions concerning your health.
Updated: