BMI Calculator
Enter your weight and height in metric or imperial units.
The formula
BMI is weight in kilograms divided by height in meters squared. At 70 kg and 1.75 m, BMI is 70 ÷ (1.75 × 1.75) = 22.9. In imperial units the same thing is 703 × weight in pounds ÷ height in inches squared; this calculator converts to metric first.
Adult BMI categories
| BMI | WHO category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25 to 29.9 | Overweight |
| 30 and above | Obesity |
BMI chart by height
| Height | Healthy range (kg) | Healthy range (lb) | BMI 25 at | BMI 30 at |
|---|---|---|---|---|
| 150 cm (4′11″) | 42–56 | 92–124 | 56 kg | 68 kg |
| 155 cm (5′1″) | 44–60 | 98–132 | 60 kg | 72 kg |
| 160 cm (5′3″) | 47–64 | 104–141 | 64 kg | 77 kg |
| 165 cm (5′5″) | 50–68 | 111–149 | 68 kg | 82 kg |
| 170 cm (5′7″) | 53–72 | 118–159 | 72 kg | 87 kg |
| 175 cm (5′9″) | 57–76 | 125–168 | 77 kg | 92 kg |
| 180 cm (5′11″) | 60–81 | 132–178 | 81 kg | 97 kg |
| 185 cm (6′1″) | 63–85 | 140–188 | 86 kg | 103 kg |
| 190 cm (6′3″) | 67–90 | 147–198 | 90 kg | 108 kg |
| 195 cm (6′5″) | 70–95 | 155–209 | 95 kg | 114 kg |
What BMI doesn’t tell you
BMI is a screening measure for populations, not a diagnosis. It can’t tell muscle from fat, so muscular people can read as overweight, and it says nothing about where fat is carried, which matters for health risk. Waist measurement is a useful second check: UK guidance from NICE suggests keeping your waist to less than half your height.
Some health bodies use lower thresholds for people of South Asian, Chinese, Middle Eastern, Black African, or African-Caribbean family background, with overweight starting at 23 and obesity at 27.5, because health risks rise at lower BMIs in those groups. The adult categories also don’t apply to children and teenagers, whose BMI is assessed against growth charts for their age and sex.
Sources: World Health Organization adult BMI classification; UK National Institute for Health and Care Excellence (NICE) guidance on BMI thresholds and waist-to-height ratio. This calculator is for information only and is not medical advice.