About this calculator
This fence calculator turns the length of your fence line into a materials list for a standard wood fence: posts set at a regular spacing, horizontal rails between them and vertical pickets across the face. It handles privacy fences with no gaps and spaced picket fences alike.
For the concrete to set the posts, use the fence post concrete calculator.
How to use it
- Measure the total length of the fence line. Measure each straight run and add them together.
- Choose the post spacing — 8 ft on center is standard and matches 8 ft rails.
- Pick the number of rails per section: two for short fences, three for 6 ft privacy fences.
- Enter the picket width and the gap between pickets, and add a post for each corner or end beyond the first run.
The formula
Sections = fence length ÷ post spacing, rounded up
Posts = sections + 1 + extra corner posts
Rails = sections × rails per section
Pickets = fence length ÷ (picket width + gap) × (1 + extra%)
A 100 ft fence with 8 ft spacing has 13 sections (the last one is shorter) and needs 14 posts. With 5½ in pickets and no gap, the fence face needs 219 pickets before the allowance for defects.
Worked example
These are the calculator’s starting values and the results they produce:
| Total fence length | 100 ft |
|---|---|
| Post spacing | 8 ft |
| Rails per section | 3 rails (5–6 ft fences) |
| Picket width | 5.5 in |
| Gap between pickets | 0 in |
| Corners and ends | 0 |
| Extra pickets for defects | 5 % |
Tips before you buy
- Check property lines and call 811 (in the US) to have utilities marked before you dig.
- Many towns require a permit and limit fence height — typically 4 ft in front yards and 6 ft in back.
- Gates need sturdier posts (often 6×6) and a dedicated section width; plan gate openings before setting posts.
- Use pressure-treated posts rated for ground contact, even if the rest of the fence is cedar.
Frequently asked questions
How many posts do I need for a 100 ft fence?
With posts every 8 ft, 100 ft needs 13 sections and 14 posts, plus one extra post for each corner or gate.
How many pickets for 8 ft of fence?
With 5½ in pickets and no gap, an 8 ft (96 in) section needs about 17.5 pickets — buy 18. With a 2½ in gap it needs 12.
How far apart should fence posts be?
Wood fence posts are usually set 6–8 ft apart on center. 8 ft is the most common because rails are sold in 8 ft lengths; use closer spacing for tall fences or windy locations.