ruling span formula

[WAlinehand1970]

Hey, guys.
I know it has been discussed before but i cant find the thread. I am looking for the Ruling Span Formula...
Thanx

[Lineman North Florida]

It's been a long time since I've thought about it but I think I remember, if not someone will get it straight. The formula for finding the Ruling Span is Average span + .66 or 2/3 x Maximum Span minus the average span= Ruling Span. I think this is it.

[arkansas traveler]

try this. ruling span = avg. span + .66(longest span - avg. span)