On any standard steel measurring tape you will find some mark at every 16 inches, What that mark is ?

Question

I have been using the measure tape for last so many years, I have ask this question to so many engineers but no satisfactory answer has been given.

Answer 1

Wall studs are commonly placed at 16" on center, the marks are for the convenience of carpenters.

You might also find smaller marks at 19.2" intervals, those are sometimes used (but not all that often) for floor joists since 5 x 19.2" = 96", the length of a sheet of plywood, this is sometimes used to save some lumber cases where 24" spacing would be too far, but the joists do not need to be as close as 16"