Free landscaping calculator
Fence Calculator — posts, rails & pickets
One shopping list for a wood privacy fence: posts, rails, pickets, and the concrete to set them.
Straight-run estimate with pickets butted tight. Corners and gates each add a post; gaps between pickets reduce the count.
How much fence material do I need?
A wood privacy fence is four shopping-list items: posts, rails, pickets, and concrete. Posts = fence length divided by post spacing, plus one to close the run. Rails = sections × 2 or 3. Pickets = fence length divided by picket width (this estimate butts them tight — a shadowbox or spaced picket style uses fewer). Concrete is per post hole. Every corner and gate adds a post beyond the straight-run count.
| Item | Quantity |
|---|---|
| Posts (4×4) | 14 |
| Rails (2×4) | 39 |
| Pickets, 5½ in | 219 |
| Concrete, 2 bags/post | 28 bags |
How deep do fence posts go?
The rule of thumb is one-third of the above-ground height, with a 2-foot minimum — so a 6-foot fence gets posts set 2 feet deep in holes about 10 inches wide, which is why posts are bought as 8-footers. In cold climates, dig below the frost line so freeze-thaw cycles can't heave the posts. Slope the concrete away from the wood at the surface so water sheds instead of pooling around the post.
6-foot vs 8-foot spacing
Eight feet is standard and uses the fewest posts. Choose 6-foot spacing for windy sites, heavier board-on-board designs, or anywhere the fence line steps down a slope — shorter sections follow grade more cleanly and each panel carries less wind load.
Frequently asked questions
How many fence posts do I need for 100 feet?
At standard 8-foot spacing, 100 feet of fence needs 14 posts (13 sections plus one post to close the run). At 6-foot spacing it takes 18. Add one post for each corner and one for each side of a gate.
How many bags of concrete per fence post?
A typical 4x4 post in a 10-inch-wide, 2-foot-deep hole takes about two 50 to 60 lb bags of fast-setting concrete. Use three bags for deeper holes, loose soil, or gate posts, which carry extra load.
How deep should fence posts be set?
Bury one-third of the post's above-ground height, with a 2-foot minimum. A 6-foot fence uses 8-foot posts set 2 feet deep. In cold climates, go below the local frost line to prevent heaving.
How many pickets do I need per foot of fence?
Standard 5.5-inch pickets butted tight run about 2.2 per foot of fence, so 100 feet takes roughly 219. Narrow 3.5-inch pickets run about 3.4 per foot. Spaced or shadowbox styles use fewer per foot.