Quick answer
Divide the fence length by the post spacing and add one to get the post count. A 100 foot fence with posts every 8 feet needs 14 posts, 26 rails at two per section, about 230 pickets that are 5.5 inches wide, and roughly 28 bags of concrete.
Fence materials by fence length
Material counts for a straight wood picket fence with posts every 8 feet, two rails per section, 5.5 inch pickets with a quarter inch gap, and 10 percent picket waste.
| Fence length | Posts | Rails | Pickets | Concrete bags |
|---|---|---|---|---|
| 50 ft | 8 | 14 | 115 | 16 |
| 75 ft | 11 | 20 | 173 | 22 |
| 100 ft | 14 | 26 | 230 | 28 |
| 150 ft | 20 | 38 | 345 | 40 |
| 200 ft | 26 | 50 | 460 | 52 |
| 300 ft | 39 | 76 | 689 | 78 |
Add one post for each corner where the run changes direction, plus gate posts.
How do you calculate fence posts, rails, and pickets?
A fence is built in sections between posts, so everything starts with post spacing. The calculator divides your total run by the spacing and rounds up to get sections, then adds one post to close the last section.
Rails are counted per section. Pickets are counted by dividing the run in inches by the picket width plus the gap, with a waste allowance for splits and bad boards. Concrete is estimated at two bags per post hole.
The formula
- Sections = fence length / post spacing, rounded up
- Posts = sections + 1
- Rails = sections x rails per section
- Pickets = (fence length x 12) / (picket width + gap), plus waste, rounded up
- Concrete bags = posts x 2
Worked example
With the starting values in the calculator (Fence length: 120 ft, Post spacing: 8 ft, Rails per section: 2, Picket width: 5.5 in, Picket gap: 0.25 in, Waste buffer: 10%, Post price: $14, Picket price: $3), the result is 16 posts at an estimated $1,052.
- Sections = 120 / 8, rounded up = 15
- Posts = 15 sections + 1 = 16
- Pickets = (120 x 12) / (5.5 + 0.25) with waste = 276
What this calculator assumes
- One straight run. Each corner or end adds posts, and gates need their own posts and hardware.
- Two bags of concrete per post hole.
- Pickets default to 5.5 inches wide, the actual width of a nominal 1x6 board.
- The budget covers posts and pickets only, not rails, concrete, fasteners, or gates.
Tips for a more accurate estimate
- Have underground utilities marked before you dig. In the United States, call 811 a few days ahead.
- Use three rails per section for fences 6 feet and taller to limit sagging and warping.
- Check local rules for fence height, setbacks, and which side must face the neighbor before buying.
- For pre-built panels, set post spacing to the panel width and buy one panel per section.
Fence Material Calculator FAQ
How many fence posts do I need for 100 feet?
With posts 8 feet apart, 100 feet of fence needs 13 sections and 14 posts. At 6 foot spacing it needs 17 sections and 18 posts.
How many pickets do I need per foot of fence?
With 5.5 inch pickets and a quarter inch gap, each picket covers 5.75 inches, so you need about 2.1 pickets per foot before waste.
How deep should fence posts be set?
A common rule is to bury about one third of the post length and to go below the local frost line. A 6 foot fence typically uses 8 foot posts set about 2 feet deep, but soil, wind, and code can require more.
How far apart should fence posts be?
Eight feet on center is common for many wood fences, but soil, wind, height, and local code can change the layout.
Does this include gates?
No. Add gate hardware, gate posts, and bracing separately because every opening is different.
Should I call before digging?
Yes. Always have utilities marked before digging post holes.
Use this estimate as a planning starting point. Product coverage, waste, local prices, code rules, and site conditions can change the final amount.