Body mass index (BMI) compares your weight with your height. It is the first screening number doctors use for weight, because it is quick and needs no equipment. It does not measure body fat directly, so it is a starting point, not a diagnosis.
How it is calculated
- Metric: BMI = weight in kg ÷ (height in meters)².
- Imperial: BMI = 703 × weight in lb ÷ (height in inches)².
Adult categories of the World Health Organization and the CDC: under 18.5 is underweight, 18.5 to 24.9 is a healthy weight, 25 to 29.9 is overweight and 30 or more is obesity. They are the same for men and women and for every age from 20.
Example
A person who is 5 ft 4 in (163 cm) and weighs 150 lb (68 kg): 703 × 150 ÷ 64² = 25.7. That is just over the line into overweight. The healthy range for this height is 108 to 145 lb (49 to 66 kg), so 5 lb (2 kg) separates this person from it. At 140 lb (64 kg) the BMI would be 24.0, inside the healthy range. If you want to get there, the calorie deficit calculator shows how long it takes at a safe pace.
Asian cut-offs
At the same BMI, people of Asian descent tend to have more body fat and a higher risk of type 2 diabetes and heart disease. A WHO expert consultation in 2004 proposed action points at 23 (increased risk) and 27.5 (high risk). Several Asian countries, including India, use lower cut-offs in their own guidelines. Choose "Asian cut-offs" above to see them.
What BMI misses
- Muscle. Athletes and people who lift weights can score "overweight" with low body fat.
- Where the fat is. Fat around the waist carries more risk than fat on the hips. A waist measurement adds what BMI cannot see.
- Age. In adults over 65, a meta-analysis of almost 200,000 people found that being overweight did not raise the risk of death. The risk was higher below a BMI of 23 and only began to rise above 33.
- Pregnancy. BMI is not used during pregnancy; doctors use the weight from before it.
Frequently asked questions
Is 140 lbs overweight for 5'4"?
No. At 5 ft 4 in (163 cm), 140 lb (64 kg) is a BMI of 24.0, inside the healthy range of 18.5 to 24.9. Overweight starts at about 146 lb (67 kg) for this height. With the Asian cut-offs, the increased-risk range starts lower, at about 134 lb (61 kg).
Is 150 lbs overweight for 5'4"?
Yes, by a small margin. At 5 ft 4 in (163 cm), 150 lb (68 kg) is a BMI of 25.7, just over the overweight line of 25. The healthy range for this height ends at about 145 lb (66 kg).
How much should a 5'5" female weigh?
A healthy weight for 5 ft 5 in (165 cm) is about 112 to 150 lb (51 to 68 kg), BMI 18.5 to 24.9. The range is the same for men and women of the same height. The BMI chart on this page lists every height from 4 ft 10 in to 6 ft 4 in.
What is the correct BMI for a female?
18.5 to 24.9, the same as for men. The adult categories do not change with sex. Women usually have more body fat than men at the same BMI, which is one reason BMI is a screening number and not a measure of fat.
What is a good BMI by age?
For adults the categories are the same at every age: 18.5 to 24.9 is healthy. Over 65, research suggests a slightly higher BMI is not harmful: a large meta-analysis found the risk of death rose below 23, not at 25. Children and teens under 20 are measured on growth charts for their age and sex instead.
Sources
- World Health Organization: Obesity and overweight, fact sheet
- CDC: Adult BMI categories
- CDC: Child and teen BMI categories (BMI-for-age percentiles)
- WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet, 2004
- Winter JE et al. BMI and all-cause mortality in older adults: a meta-analysis. Am J Clin Nutr, 2014
By Calcelate Team. Formula from the sources above.
- 2026-10-02 · Formula and texts checked