String test A:
Measuring the coronet band to the center of the knee on the foreleg.
If it reads 12 3/4 inches, she would get to be 12 3/4 hands tall.
14 1/2 inches = 14 1/2 hands
And so on...
String test B:
You measure the horse from the point of the ergot to the point of the elbow.
You take that measurement and (keeping your hand on the elbow) circle your other hand up (like a compass) extending UP beyond the withers.
How high it reaches is how tall the horse will be, except:
If the horse is still a weanling, add 2 inches to that height,
And if it's a yearling add one inch.
To estimate height use a calculator, and the formula is: birth height in inches divided by .6356, (this would be divided by 4 to get the hands.)
Convert the decimals as follows:
__.00 = 0/4 = __:0hh
__.25 = 1/4 = __:1hh
__.50 = 1/2 = __:2hh
__.75 = 3/4 = __:3hh