BMI of a 155 cm, 51 kilogram person

What is the BMI of a man or woman who weighs 51 kilos and is 155 centimeters tall?
cm
kg
BMI = 21.23
Note: BMI is the same for men and women.

Am I Overweight?

Here are the BMI standards as set by the World Heath Organization:

BMICategory
< 18.5Underweight
18.5 - 25Healthy Weight
25 - 30Overweight
> 30Obese

In the United States, the average BMI for adults is 28.8.

BMI Formula

Metric
BMI = kg / m2

Imperial
BMI = (lbs * 0.45359237) / (inches * 0.0254)2

Simplified
BMI = 703 * lbs / inches2

Is BMI Worth Using?

Body Mass Index is a very simplistic method of determining whether a person is overweight. It does not taken into account a person's frame, gender, or muscularity. Furthermore, at least one study has suggested that slightly overweight people may live longer than people in the "normal" range.

Nevertheless, BMI is highly correlated with body fat % and is a decent enough yardstick of a healthy weight.

Body fat estimates for a person with a BMI of 21.23
These are rough estimates based on a formula, and do not reflect differences in muscularity, body types, etc...
Age Male Female
18 13.4% 24.2%
19 13.6% 24.4%
20 13.9% 24.7%
21 14.1% 24.9%
22 14.3% 25.1%
23 14.6% 25.4%
24 14.8% 25.6%
25 15.0% 25.8%
26 15.3% 26.1%
27 15.5% 26.3%
Age Male Female
28 15.7% 26.5%
29 15.9% 26.7%
30 16.2% 27.0%
31 16.4% 27.2%
32 16.6% 27.4%
33 16.9% 27.7%
34 17.1% 27.9%
35 17.3% 28.1%
36 17.6% 28.4%
37 17.8% 28.6%
Age Male Female
38 18.0% 28.8%
39 18.2% 29.0%
40 18.5% 29.3%
41 18.7% 29.5%
42 18.9% 29.7%
43 19.2% 30.0%
44 19.4% 30.2%
45 19.6% 30.4%
46 19.9% 30.7%
47 20.1% 30.9%
Age Male Female
48 20.3% 31.1%
49 20.5% 31.3%
50 20.8% 31.6%
51 21.0% 31.8%
52 21.2% 32.0%
53 21.5% 32.3%
54 21.7% 32.5%
55 21.9% 32.7%