Decking Calculator
Calculates decking boards and lineal metres needed from deck size, board width and gap.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the deck length and width.
- Enter board width, gap and board length.
- Read rows, lineal metres and boards needed.
How it works
Rows = width ÷ (board width + gap); lineal metres = rows × length; boards = lineal metres ÷ board length, rounded up.
Worked example
6 × 4 m deck, 90 mm boards, 4 mm gap. ≈ 43 rows, ~256 lineal m.
Tips
- Runs entirely in your browser. Your inputs are not saved or transmitted.
Frequently asked questions
Should I add waste?
Yes — allow ~10% for cuts, especially on angled or picture-frame decks.
Privacy?
Runs entirely in your browser. Your inputs are not saved or transmitted.
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Cite this tool
Zerdly. (2026). Decking Calculator. Retrieved from https://www.zerdly.com/tools/decking-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.