Healthy Body Mass Index

According to WHO, people should aim to have a body mass index (BMI) between 18.5 & 25kg per metres square. Which means a healthy BMI should be between 18.5-25kg/m^2.
How do I know my BMI? If you are using a calculator, 

BMI= body weight in kg ÷ body height in metres e.g, 1.72m raised to power of 2. 

BMI above 25 is considered as overweight and unhealthy exception of wrestlers and rugby players having muscle mass higher than body fat.

What's your BMI?

Mine: 20.9kg/m^2. (Healthy weight).