What this calculator does
Fencing & decking materials works out posts, rails and boards for a run of fence or deck. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaPosts = ⌈length/spacing⌉ + 1; Boards = length / (board width + gap)
The inputs explained
| Field | What to enter |
|---|---|
| Total length (m) | A number, measured in m. Starts at 24. |
| Post spacing (m) | A number, measured in m. Starts at 2.4. |
| Board width (mm) | A number, measured in mm. Starts at 140. |
| Gap between boards (mm) | A number, measured in mm. Starts at 5. |
| Height (rows of boards) (m) | A number, measured in m. Starts at 1.8. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with total length
Every other input is held at the calculator’s starting values while total length varies. Select any row to load that scenario into the calculator.