Deck Board Calculator
Estimate how many stock boards to buy from deck size, board face width, gap, and waste. Units: feet and inches. Print or copy a shopping list before you buy.
HomeFixMath — Deck board shopping list
Shopping list
Enter valid measurements above to build your list.
- Decking boards (match species, grade, and face width)
- Joist hangers / fasteners rated for outdoor use
- Hidden clips or deck screws
- Optional: fascia boards and railing posts
Retailer buy links will appear here after affiliate networks are approved (Impact / CJ / Awin). See Affiliate Disclosure.
Estimates only. Confirm actual board face width and spacing with the product. Not structural or code approval.
How we calculate
- Effective pitch = board face width + gap (inches).
- Rows = ceil( span perpendicular to boards × 12 ÷ pitch ).
- Pieces per row = ceil( span along boards ÷ stock length ).
- Raw boards = rows × pieces per row; buy = ceil(raw × (1 + waste%)).
- Linear ft with waste = rows × along-span × (1 + waste%).
Example: 16×12 ft deck, boards parallel to length, 5.5 in face, 1/8 in gap, 12 ft stock, 10% waste → pitch 5.625 in → 26 rows → 2 boards/row → 52 raw → 58 to buy.
FAQ
What face width should I use? Use the actual dressed width (often 5.5 in for “6 in” lumber, or the manufacturer’s stated face for composites).
How big a gap? Many wood decks use about 1/8 in; composites follow the brand’s clip or spacer guidance. Change the gap field to match.
Why add waste? End cuts, bad boards, and picture-frame borders eat stock. 10% is a common planning buffer.
Does this size joists or footings? No — this tool only estimates decking boards, not framing or permits.
Estimates only. Confirm with product labels, local code, and your measurements. Not engineering advice.