Calculate adult body mass index from weight and height in metric or imperial units, with the matching adult reference category.
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At 70 kg and 175 cm, BMI is 22.86, inside the 18.5 to under 25 range. In imperial units, 180 lb at 5 ft 10 in gives 25.83, just above the boundary of 25, while 92 kg at 180 cm gives 28.4.
BMI is weight in kilograms divided by height in meters squared, so 70 kg at 175 cm gives 22.86. Imperial inputs are converted first: pounds are multiplied by 0.45359237 to get kilograms, and feet and inches are turned into total inches and multiplied by 0.0254 to get meters, before the same formula is applied. The category is chosen from the unrounded value.
The adult categories used are under 18.5, 18.5 to under 25, 25 to under 30, and 30 or more. They are screening references, not a diagnosis: BMI does not separate muscle from fat or show where fat is stored, and it is not used this way for children, teenagers or pregnancy. Some health authorities use lower cut-offs for people of Asian descent.
Choose metric or imperial units, then enter body weight and height. In metric mode, 70 kg and 175 cm give a BMI of 22.86. In imperial mode, 180 lb at 5 ft 10 in gives 25.83 because the tool converts pounds to kilograms and feet and inches to meters before applying the same formula. Use a recent measurement taken without shoes; entering a height 2 cm too short, for example, raises the result for 70 kg from 22.86 to about 23.39.
The adult reference categories used here are below 18.5, 18.5 to under 25, 25 to under 30, and 30 or higher. At a height of 175 cm, the middle range runs from about 56.66 kg to just under 76.56 kg. A result such as 25.83 is only just above a boundary, while 28.4 for 92 kg at 180 cm sits well inside the 25 to 30 range, and 50 kg at 165 cm gives 18.37, just below 18.5. A small movement across a line is not a sudden change in health.
BMI is a population screening measure based only on weight and height. It does not distinguish muscle from fat, does not show where fat is stored, and does not account for pregnancy. Children and teenagers are assessed with age- and sex-specific percentiles, not these adult categories, and several health organizations use different cut-offs for some populations, including lower thresholds in parts of Asia. Use the number as a starting point for a conversation with a qualified professional, not as a diagnosis.
| Input | Result |
|---|---|
70 kg · 175 cm | 22.86 |
50 kg · 165 cm | 18.37 |
92 kg · 180 cm | 28.4 |
180 lb · 5 ft 10 in | 25.83 |
76.56 kg · 175 cm | 25 |
Multiply your height in meters squared by 18.5 and by 25. At 175 cm, the range runs from about 56.66 kg to just under 76.56 kg; exactly 76.56 kg gives a BMI of 25, the start of the next category. Small moves across a boundary do not signal a sudden change in health.
Height matters more than weight because it is squared. For 70 kg, entering a height 2 cm too short raises the result from 22.86 to about 23.39. Measure height without shoes and weight at a similar time of day, and compare results measured the same way.
Only with care. Muscular people can show a high BMI without excess fat, and older adults may lose muscle while BMI stays the same. Children and teenagers are assessed with age- and sex-specific growth percentiles instead of these adult categories. Use the number as a starting point for a conversation with a health professional.