Fence Calculator: How Many Pickets Do I Need?
Enter the length of the fence and how it is built. You will get pickets, posts and rail lumber — the three things you have to buy separately, and the three that are easy to get out of step with each other.
Fence run and style
Measure the whole run including gates — the post line goes all the way.
This covers pickets, posts and rails only — not concrete, hardware, gate furniture or the extra post a corner needs. Terrain matters too: a slope means stepped or racked sections, which changes the picket count.
How many fence pickets do I need?
Divide the run by the pitch of a picket — its actual width plus whatever gap the style calls for. A privacy fence has no gap, so the pitch is just the board width; a spaced picket fence has a gap that can cut the board count by a third.
Posts are always one more than the number of bays: a fence with 13 sections has 14 posts, because both ends need one. It is a small thing that is easy to be short on.
Fence styles and the gap
| Style | Gap | What it looks like |
|---|---|---|
| Privacy | 0 in | Boards butted together, no gap |
| Spaced picket | 2 in | A classic gapped picket fence |
| Shadowbox | 4 in | Alternating boards each side of the rails |
The gap has a large effect on cost. Over 100 feet, moving from a butted privacy fence to a 2 in gap saves nearly 60 boards — which is why the style is worth deciding before you price the job, not after.
Posts, bays and rails
Post spacing is a trade-off: 8 ft bays are common and use fewer posts, but 6 ft bays sag less and hold up better in wind. Rails run between posts, so each rail is one bay long and the rail count is bays times rails per section.
Two rails suit a fence up to about four feet. Taller fences usually take three, and a six-foot privacy fence almost always does — without a middle rail the boards bow.
How to measure a fence line
The post line runs the whole way; gates are subtracted from the pickets separately.
A nominal 1 × 6 is about 5.5 inches. Check before you count on it.
Each corner needs its own post beyond what a straight run implies — worth adding to the post count by hand.
Common mistakes
- Buying one post per bay and coming up one short at the end.
- Using the nominal board width instead of the actual 5.5 inches.
- Forgetting the middle rail on a tall privacy fence.
- Pricing a privacy fence and then building a spaced one, or the reverse.
Setting the posts in concrete?
Work out the concrete for the post holes before you start digging.
Open the Concrete Calculator →