Ruler For Frets ?

Hi all

What kind of ruler do you all use to layout for the frets? I found a steel ruler marked 64th & 32nd on one side and 50ths &100ths on the other side. comes in 3/4" or 1 1/8" wide and 18" or 24" long.

Just not sure if this is the right tool to use.

Thanks

Ron