Fence planning
How Many Fence Posts, Pickets, and Bags of Concrete?
Divide the fence length by the post spacing, round up, and add one to get posts. A 100 foot fence at 8 foot spacing needs 14 posts, 26 rails with two per section, about 230 pickets at 5.5 inches wide, and about 28 bags of concrete.
Open the fence material calculatorPosts and sections
A section is the span between two posts. Divide the run by your spacing and round up to get sections, then add one post for the end. Wood privacy fences commonly use 8 foot spacing, and 6 foot spacing is used for taller fences or windy sites.
Count each straight run separately. Corner posts are shared between two runs, and every gate needs a sturdy post on each side.
Rails and pickets
Rails run horizontally between posts. Fences up to about 5 feet tall typically use two per section, and 6 foot fences use three.
For pickets, add the picket width and the gap to get the coverage of one picket, then divide the fence length in inches by that number. A nominal 1x6 picket is actually 5.5 inches wide. Add about 10 percent for splits and warped boards.
| Item | Math | Quantity |
|---|---|---|
| Sections | 100 / 8, rounded up | 13 |
| Posts | 13 + 1 | 14 |
| Rails | 13 x 2 | 26 |
| Pickets | 1,200 in / 5.75 in, plus 10% | 230 |
| Concrete | 14 posts x 2 bags | 28 bags |
Concrete per post
A common guideline is a hole about three times the post width and deep enough to bury roughly one third of the post, extending below the frost line in cold climates. A 10 inch wide, 30 inch deep hole around a 4x4 post takes about two 80 lb bags. Larger gate and corner posts take more.
What the simple count misses
Check these before you treat any material list as final.
- Gates: hardware, heavier posts, and diagonal bracing.
- Slopes: stepped or racked sections change picket length and count.
- Fasteners: exterior-rated screws or ring-shank nails, two per picket per rail.
- Rules: property lines, height limits, setbacks, and homeowner association approvals.
- Utilities: have lines marked before digging. In the United States, call 811.
- Posts = (fence length / spacing, rounded up) + 1.
- Pickets = fence length in inches / (picket width + gap), plus 10 percent.
- Plan about two bags of concrete per standard post, and call 811 before digging.
Run the numbers
The Fence Material Calculator applies this math to your own measurements and shows each step. Best for early planning before requesting quotes or shopping for a simple fence line.