Fence Post Count
The number of spans is length over spacing, but you need one more post than that, because both ends carry a post. Forgetting that extra one is the classic materials mistake.
Your numbers
Posts needed
11
Count
10
Post spacing
2.4m
What it means
11 posts for 10 spans, giving an even 2.4 m spacing.
Formula
Posts needed = Fence length ÷ Post spacing + 1
For a fence that closes in a loop, the start and end share a post, so posts equal spans.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Fence length (m)The total run the fence covers. | 24 | 0 and up |
| Post spacing (m)The spacing from one post to the next. | 2.4 | 0.1 and up |
Step by step
Quick reference table
Results when only Fence length (m) changes and everything else stays put.
| Fence length (m) | Posts needed | Count | Post spacing (m) |
|---|---|---|---|
| 12 | 6 | 5 | 2.4 |
| 18 | 9 | 8 | 2.25 |
| 24 | 11 | 10 | 2.4 |
| 36 | 16 | 15 | 2.4 |
| 48 | 21 | 20 | 2.4 |
What each result means
| Result | At default values |
|---|---|
| Posts neededPosts including both ends — one more than the spans. | 11 |
| CountA plain count of items; it often ends up as the denominator. | 10 |
| Post spacing (m)The spacing from one post to the next. | 2.4 |
Common mistakes
For a fence that closes in a loop, the start and end share a post, so posts equal spans.
Glossary
- Fence length
- The total run the fence covers.
- Post spacing
- The spacing from one post to the next.
- Posts needed
- Posts including both ends — one more than the spans.
- Count
- A plain count of items; it often ends up as the denominator.
Frequently asked questions
Q. How is Fence Post Count calculated?
Posts needed = Fence length ÷ Post spacing + 1 — The number of spans is length over spacing, but you need one more post than that, because both ends carry a post. Forgetting that extra one is the classic materials mistake.
Q. Can you walk through an example?
With Fence length 24m, Post spacing 2.4m, the answer is Posts needed 11.
Q. What do I need to enter?
Enter Fence length, Post spacing. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Fence length (m) moves the answer to Fence length (m) 12 → Posts needed 6 and Fence length (m) 48 → Posts needed 21. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
For a fence that closes in a loop, the start and end share a post, so posts equal spans.
Related calculators
Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.