Contractor & construction
Fence Calculator
Works fence quantities, where the post count is one more than the sections.
Result
Assumes a straight run with no gates. Each gate needs heavier posts and hardware, and corners need an extra post. Add them manually.
Get a Free Business AuditHow the calculation works
Posts equal the run divided by the spacing, plus one, with additional posts at each corner, end and gate. Rails follow the section count, pickets follow the length and spacing, and concrete follows the post count and hole size. Gates need their own posts and hardware.
What moves the number
- Post spacing and the total run.
- Corners, ends and gate openings, each needing posts.
- Picket spacing, which changes the count substantially.
- Concrete per post hole.
Where this one goes wrong
Forgetting the extra post is the classic error, since a run of sections has one more post than sections, and corners and gates each add posts beyond that. Count them from a sketch. Gate posts also carry more load than line posts and generally need deeper or larger footings, which is a real difference rather than a refinement, and a gate post that moves makes the gate unusable.
Before you quote
- Count posts from a sketch including corners, ends and gates.
- Size gate post footings larger than line posts.
- Check local rules on height, setback and whether a permit applies.
Questions
About this calculator
How many posts does a fence need?
The run divided by the spacing plus one, with additional posts at every corner, end and gate. Forgetting the extra post is the classic takeoff error, and corners and gates add further posts beyond the simple division.
Do gate posts differ from line posts?
Yes, they carry more load and generally need deeper or larger footings. It is a real structural difference rather than a refinement, and a gate post that shifts makes the gate unusable however good the rest of the fence is.
Are there rules about fences?
Commonly, on height, setback from boundaries and sometimes materials, set locally and sometimes by a homeowner association. Whether a permit is needed varies, and it is worth checking before the posts go in rather than after.
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How to use this calculator
- Fence length (ft) (ft). Enter your own figure; the page starts at 150 ft.
- Post spacing (ft) (ft). Enter your own figure; the page starts at 8 ft.
- Fence height (ft) (ft). Enter your own figure; the page starts at 6 ft.
- Rails per section. Enter your own figure; the page starts at 3.
- Picket width (inches) (in). Enter your own figure; the page starts at 5.5 in.
- Cost per post ($). Enter your own figure; the page starts at $14.
The result updates as you type, so you can try a figure, see what it does to posts needed, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Fence length (ft) | 150 ft |
| Post spacing (ft) | 8 ft |
| Fence height (ft) | 6 ft |
| Rails per section | 3 |
| Picket width (inches) | 5.5 in |
| Cost per post | $14 |
| Cost per rail | $9 |
| Cost per picket | $3.2 |
What comes out
| Result | Value |
|---|---|
| Posts needed main result | 20 |
| Rails needed | 57 |
| Pickets needed | 328 |
| Material cost | $1,843 |
A 150 ft fence needs 20 posts across 19 sections, with 57 rails and 328 pickets, about $1,843 in materials plus roughly 40 bags of post concrete.
How sensitive the answer is
Holding everything else steady and changing only cost per post, this is what happens to posts needed. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cost per post ($) | Posts needed |
|---|---|
| $7 | 20 |
| $10.5 | 20 |
| $14 example above | 20 |
| $21 | 20 |
| $28 | 20 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Fence length (ft) (ft)
- Measured in ft, starting at 150 ft.
- Post spacing (ft) (ft)
- Measured in ft, between 0 and 20, starting at 8 ft.
- Fence height (ft) (ft)
- Measured in ft, between 0 and 20, starting at 6 ft.
- Rails per section
- A number, between 0 and 10, starting at 3.
- Picket width (inches) (in)
- Measured in in, between 0 and 24, starting at 5.5 in.
- Cost per post ($)
- A money amount, starting at $14.
- Cost per rail ($)
- A money amount, starting at $9.
- Cost per picket ($)
- A money amount, starting at $3.2.
What the results tell you
| Result | What it is |
|---|---|
| Posts needed | The headline result. A number. |
| Rails needed | A number. |
| Pickets needed | A number. |
| Material cost | A money figure. |
Overhead is where these go wrong
Pricing and margin figures are only as good as the cost you put in. If your cost covers parts and wages but not the van, the insurance, the phone and the unbilled hours, the markup is paying for those before it becomes profit, and the margin you think you are making is not the one you are making.
Keep going
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