Height at maturity calculated by age of the foal in months.
First look up the age of your young horse in months, then, look in the row right of the monts what height the horse currently has. On the top of that row you can see how big your horse is going to grow up when it has reached maturity.
(the chart has proven to be 90% accurate (1/2" plus or minus)).
To calculate in centimeters:
centimeters = inch X 2.54
(inch = centimeters : 2.54)