Decking calculator
Estimate parallel rows with one continuous board per row.
Formula
Rows = ceil((deck width+gap)/(board width+gap)); boards = ceil(rows × (1+extra/100))
Cut length per row: 12 ft · Clear deck width: 10 ft · Actual board width: 5.5 in · Side gap: 0.1875 in · Installed rows ≈ ceil((((10 ft × 0.3048 m/ft)+(0.1875 in × 0.0254 m/in))÷((5.5 in × 0.0254 m/in)+(0.1875 in × 0.0254 m/in)))×(1-8.881784197001252e-16)) · Boards with spares ≈ ceil(((22)×(1+(5)÷100))×(1-8.881784197001252e-16)) · Total cut length ≈ (24)×(12 ft × 0.3048 m/ft)
How to use
- Enter clear deck length and width.
- Enter board width, side gap and spares.
- Read boards and their total cut length.
Examples
- Five 20 cm boards with four 1 cm gaps cover 1.04 m.
Frequently asked questions
How long must boards be?
Each board must span the entered deck length. Purchase longer stock if trimming is needed.
Are gaps universal?
No. Use the product’s temperature and installation instructions.
Does this include the frame?
No. Joists, end joints, borders, fasteners and structural checks are separate.
Sources
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