Deck Material Calculator — Full Material List for Your Deck
Get the complete material list for a deck: decking boards, joists, posts, concrete footings and fixings, priced with your local rates. Enter deck dimensions and board size, and the calculator builds the bill of materials with waste included.
Deck type
Plan view (from above)
Shopping list — Raised deck
Decking boards and cladding
Structural timber
Fasteners and brackets
Foundations
Railing
✓ Result ready — save to project
Free to try — no sign-up
Plan the whole job — not just this calculation
Save results to a project: budget and shopping list build themselves, and the whole plan exports as a PDF. Draw your floor plan and room sizes pre-fill the calculators.
How the deck material list is calculated
- 1Deck area = length × width
- 2Decking boards: area ÷ (board width + gap) = running metres, plus 5–10% waste
- 3Joists: deck dimension ÷ joist spacing + 1 (400 mm centres for 21 mm boards, 600 mm for 28 mm)
- 4Posts and beams: from the span grid; footings: one concrete pour per post below frost depth
- 5Fixings: two screws per board per joist crossing
- 6Each line gets a unit price — edit the presets to your local supplier rates
Worked example
Deck: 5 × 4 m = 20 m². Boards 28×120 mm with 5 mm gap, joists at 600 mm centres, 6 posts.
Material list: 168 running metres of decking (160 + 5% waste), 8 joists at 5 m, 6 posts, ~0.11 m³ of footing concrete and roughly 1,300 deck screws.
Frequently asked questions
What materials do I need to build a deck?
Decking boards, joists, a ledger or beams, posts, concrete for footings, joist hangers or structural screws, and deck screws. On soft ground add gravel for drainage under footings. The calculator counts each from your deck dimensions.
How do I calculate decking boards from deck size?
Divide deck area by the effective board width (board + gap): a 120 mm board with a 5 mm gap covers 125 mm, so each m² needs 8 running metres. Add 5–10% for cuts.
How many joists does a deck need?
Deck width ÷ joist spacing + 1. A 4 m wide deck at 600 mm centres needs 8 joists; at 400 mm centres, 11. Thinner boards need the tighter spacing.
How much does decking material cost?
It depends almost entirely on the board you choose — pressure-treated softwood, hardwood and composite span a several-fold price range per running metre. Enter your local board price and the calculator totals the real list; there is no honest single per-m² number.
Should I buy extra decking material?
Yes — 5% extra on boards for straight decks, 10% for diagonal layouts, plus a few spare boards from the same batch for future repairs. Timber colour varies between batches.