Brian Cryer's Glossary of IT Terms with Links

BMI

BMI

Body Mass Index.

BMI is a widely used indication of obesity.

The Body Mass Index for a person is calculated by dividing the individual's weight in kg by their height in meters squared.

BMI =	weight (kg)
	height (m) x height (m)

The resulting BMI figure gives an indication of whether the individual is underweight, overweight or obese:

BMI < 20	underweight
BMI ≥ 20 and ≤ 25	normal / healthy
BMI > 25	overweight
BMI ≥ 30	obese

Whilst not covering all combinations, the following table of height vs weight shows corresponding BMI scores:

Weight		Height
		3' 11"	4' 3"	4' 7"	4' 11"	5' 3"	5' 7"	5' 11"	6' 3"	6 '7"
		1.2m	1.3m	1.4m	1.5m	1.6m	1.7m	1.8m	1.9m	2.0m
6st 4oz	40kg	28	24	20	18	16	14	12	11	10
7st 1oz	45kg	31	27	23	20	18	16	14	12	11
7st 12oz	50kg	35	30	26	22	19	17	15	14	13
8st 10oz	55kg	38	33	28	24	21	19	17	15	14
9st 7oz	60kg	42	36	31	27	23	21	19	17	15
10st 3oz	65kg	45	38	33	29	25	22	20	18	16
11st 0oz	70kg	49	41	36	31	27	24	22	19	18
11st 11oz	75kg	52	44	38	33	29	26	23	21	19
12st 8oz	80kg	56	47	41	36	31	27	25	22	20
13st 6oz	85kg	59	50	43	38	33	29	26	24	21
14st 3oz	90kg	63	53	46	40	35	31	28	25	23
15st 0oz	95kg	66	56	48	42	37	33	29	26	24
15st 11oz	100kg	69	59	51	44	39	35	31	28	25

These are colour coded: red for over weight, pink for under weight and green for a normal healthy weight.

The BMI score should only be treated as a guide to weight problems and should not be considered in isolation. For example men are generally heavier than women, but this is not taken into account in the BMI score. Similarly fit people generally have less fat and more muscle and this also is not reflected in the score. There is also some disagreement over whether underweight should be treated as less than 18.5 or less than 20. So treat BMI scores as a guide only.