Calculating your posts needed is straightforward once you know the Fence formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Fence Calculator.
What is Fence?
The Fence calculation tells you your posts needed from a few simple inputs. The figure you are solving for here is the posts needed.
The Fence formula
This calculation combines several inputs through a multi-step method rather than a single one-line formula. Enter the values below and the calculator resolves each step in order. The inputs it needs are:
- Fence length — a value measured in ft. Example: 100 ft.
- Post spacing — a value measured in ft. Example: 8 ft.
How to calculate it step by step
- Write down the fence length (for example, 100 ft).
- Write down the post spacing (for example, 8 ft).
- Apply the formula above to get your posts needed.
- Double-check the result with the Fence Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Fence length | 100 ft |
| Post spacing | 8 ft |
| Posts needed | 14 |
| Fence sections | 13 |
With fence length of 100 ft and post spacing of 8 ft, the posts needed works out to 14.
Example 2
With fence length of 200 ft and post spacing of 8 ft, the posts needed works out to 26.
| Result | Value |
|---|---|
| Posts needed | 26 |
| Fence sections | 25 |
Example 3
With fence length of 50 ft and post spacing of 8 ft, the posts needed works out to 8.
| Result | Value |
|---|---|
| Posts needed | 8 |
| Fence sections | 7 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Fence Calculator does it instantly, for free, with the formula and a worked example built in.
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