# Fence Calculator

> Enter each run of fence, the post spacing and the number of gates. Choose panels or pickets with rails. You get the posts, panels or pickets, the post length and the bags of concrete. Three runs of 60, 40 and 60 ft with one gate need 24 posts and 20 panels.

Canonical: https://receiptscanner.co/tools/fence-calculator
Updated: 2026-10-28 · Sources re-checked by: 2027-10-28

This is a free interactive calculator that runs in the browser. Nothing you type is stored or sent. Results are estimates.

## How it works

Sections per run = run length ÷ post spacing, rounded up. Posts = sections + 1 for each open run, or just the sections if the fence goes all the way round a yard. A gate takes the place of one section, so it adds no posts: panels = sections − gates. Pickets per section = section length ÷ (picket width + gap), rounded up, and rails = sections × rails per section. Post length = fence height + hole depth, rounded up to a stocked length. Concrete per hole = the round hole (π × (diameter ÷ 2)² × depth) minus the square post, then bags from the bag yields (50 lb 0.375, 80 lb 0.60 cubic feet).

**Posts for one open run, by length and spacing**

| Run | 6 ft spacing | 8 ft spacing | 10 ft spacing |
| --- | --- | --- | --- |
| 20 ft | 5 | 4 | 3 |
| 50 ft | 10 | 8 | 6 |
| 100 ft | 18 | 14 | 11 |
| 200 ft | 35 | 26 | 21 |

**Post length to buy for a 30 in hole**

| Fence height | Post needed | Stocked post |
| --- | --- | --- |
| 3 ft | 5.5 ft | 6 ft |
| 4 ft | 6.5 ft | 8 ft |
| 5 ft | 7.5 ft | 8 ft |
| 6 ft | 8.5 ft | 10 ft |
| 8 ft | 10.5 ft | 12 ft |

## Worked example: runs of 60, 40 and 60 ft, 8 ft spacing, one gate, 6 ft fence

1. Sections: 60 ÷ 8 = 7.5 so 8, 40 ÷ 8 = 5, 60 ÷ 8 so 8. Together 21.
2. Posts on three open runs: 21 + 3 = 24. One gate takes a section: 21 − 1 = 20 panels.
3. Post length: 6 ft above ground + 2.5 ft in the hole = 8.5 ft, so buy 10 ft posts.
4. Concrete: a 10 in hole 30 in deep around a 3.5 in post is 1.15 cubic feet, × 24 posts = 27.6 cubic feet.
5. That is 47 bags of 80 lb, or 74 bags of 50 lb. With pickets instead: 320 pickets at 5.5 in with a 0.5 in gap, and 40 rails.

## FAQ

### How do I calculate how many fence posts I need?
Divide each run by the post spacing, round up to whole sections, and add one post for each open run. A closed loop needs one post per section.

### How far apart should fence posts be?
Prefabricated panels set the spacing, often 6 or 8 ft. For built-on-site fences 6 to 8 ft is common. Check your panel width, the rails and your local rules.

### How deep should fence posts be?
A common rule is about a third of the post's total length in the ground, and below the frost line in cold places. Local frost depth and soil differ, so enter your own depth.

### How many bags of concrete per fence post?
It depends on the hole size and the post. A 10 in hole 30 in deep around a 4×4 takes about 1.15 cubic feet, which is a little under two 80 lb bags per post.

### Does a gate need extra posts?
A gate needs sturdy posts on both sides, but they are usually the section posts you already counted. Heavy or wide gates may need larger posts, so confirm with the gate maker.

### How many pickets do I need?
Divide the section length by the picket width plus the gap, and round up. A picket 5.5 in wide with a 0.5 in gap in an 8 ft section takes 16.

## Sources

- [QUIKRETE Concrete Mix 1101 data sheet: bag yields used for the post concrete (50 lb 0.375 and 80 lb 0.60 cubic feet)](https://www.quikrete.com/PDFs/DATA_SHEET-Concrete%20Mix%201101.pdf) (checked 2026-10-28)
- [Fence: common styles, posts and rails (general reference)](https://en.wikipedia.org/wiki/Fence) (checked 2026-10-28)

This calculator is an estimate for planning. Check post spacing, depth and height limits with your local building department and the fence maker, and call before you dig to have buried lines marked.