Fence calculator

Sections = run length ÷ maximum section length, rounded up. A single open straight run needs one more post than sections.

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Run length

Maximum section length

Answer

…

Sections = run length ÷ maximum section length, rounded up. A single open straight run needs one more post than sections.

More results

Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

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Formula and assumptions

This counts one straight run with two ends and no gates. Corners, shared posts, closed loops and manufacturer spacing rules require their own layout.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using Fence calculator

Sections = run length ÷ maximum section length, rounded up. A single open straight run needs one more post than sections.

This counts one straight run with two ends and no gates. Corners, shared posts, closed loops and manufacturer spacing rules require their own layout.

Next: Board foot calculator

A worked example

With run length = 30, maximum section length = 8, the posts for one straight run is 5.

Next: Roof pitch calculator

Before you use the result

This counts one straight run with two ends and no gates. Corners, shared posts, closed loops and manufacturer spacing rules require their own layout.

Example results for run length

These examples use Maximum section length: 8. They are reference calculations, not recommended settings.

Run length	Posts for one straight run
15	3
30	5
60	9

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ToolOctopus. “Fence calculator.” Updated 2026-09-26. https://tooloctopus.com/fence-calculator.

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