How big in in or cm are the letters of the eye chart?

Question

I'm trying to draw my own and I need to know how big they need to be. I can find samples of eye charts on the internet, but I don't know if when I print them, they are the same size as the real charts. I just need the measurement for the 20/20 line. Thanks!

Answer 1

8.726 mm, but for what distance?

Ans.  20 feet

for a 14 foot distance for 20/15 letters would be 4.58 mm.

for 20/40 at 15 feet it would be 13.1 mm.

The letters are 5 minutes of angle high for 20/20

Answer 2

8.726 mm.