The Length Spanned by Evenly Spaced Objects calculator computes the Length (L) covered by a number (n) of objects (e.g. posts, studs, joists, rafters, trusses, lights, rebars) that are evenly spaced at a distance (oC).
On Center Uses
Fences
Floor Joists
Wall Studs 
Rebar Mats
INSTRUCTIONS: Choose your preferred units, and enter the following:
- (oC) Even Spacing between objects (e.g., 16" on-center spacing of studs)
- (n) Number of Objects being spread over the distance (e.g. 12 studs)
Total Length (L): The calculator returns the length of the group of objects (wall, fence) in feet. However, this can be automatically converted to other length units (e.g. meters) via the pull down menu.
The Math
The on center calculation is fairly easy. However, people typically fail to account for the first object. So, if you want to spread 4 posts (n) out to create a fence 24 feet long (L), you can not spread them out where spread = 24 ft/4. This forgets that the first post is at position zero. You a have to reduce the number of posts by one for the first post. In this case, the calculation would be 24 ft/3 (3 = n-1), which 8 ft separation.
