Decking Calculator
Calculate decking materials from area and board size.
%
Boards to buy
47
21 rows × 2 boards per row
Deck area
12 m²
Exact boards
42
Rows
21
In-depth explanation
Estimate how many deck boards you need from deck size, board size, and gap between boards, with wastage. Everything runs locally in your browser — your inputs are not uploaded to produce the result.
Boards need spacing for drainage and expansion — often a few millimetres. This counts surface boards only. Frame materials are separate.
Around 10% is a sensible starting point for cuts and defects. Tweak the inputs above to compare options, then copy or note the result you need.
Frequently asked questions
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