Is there a standard ratio fixed for the dimensions of arms of the plain Cross?

The plain Cross is perhaps the most frequently used symbol on the earth. One can see a distinct pattern in the dimensions of the horizontal and vertical beams of the Cross . Many years ago, I heard that the ideal ratio of the length of the vertical arm and each of the horizontal arms measured from the junction is 2:3. To elaborate, if the vertical arm above the junction is two feet long, each of the horizontal arms should be of three feet. One is not sure if a proportion is fixed for the vertical beam running downwards from the junction. The question is :Is there a standard ratio fixed for the dimensions of arms of the plain Cross ? If there is one, does it have a historical backdrop, or is it just a matter of aesthetic considerations ? PS: a typical example of aesthetic considerations is the dimensions of National Flags. The Indian National Flag has the prescribed ratio of 2:3 for width and length. The American Flag has 1:1.9 .The ratio is determined by the features of the flag and the prospects of the best look.