Picket Spacing Calculator

Post spacingrails

How to measure

Measure the clear space between the faces of two posts, not post center to center.

Section

Posts 8 ft on center with 3.5 in wide posts leave 92.5 in between them.

Pickets

The calculator fits as many pickets as needed so no gap is bigger than this.

Pickets per section

15 pickets

Gap of 2 1/2 in between pickets; 15 pickets for 1 section

Pickets per section15 pickets
Exact gap2.500 in
Gap to the nearest 1/16 in2 1/2 in
On-center spacing6 in
Gaps per section16
Sections1
Total pickets15 pickets

Assumes equal gaps between every picket and at both posts. Mark the first picket 2 1/2 in from the post, then every 6 in on center.

See the formula, sources and worked examples on Matholio