Deck Material Calculator
Enter your deck dimensions and get a complete material list — boards, joists, footings, concrete, fasteners, railing, and an optional cost estimate. Every input is saved in the URL; bookmark or share to keep your numbers.
Enter deck length and depth to see your material list.
Railing (3 sides)
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Estimated total cost
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What do these results mean?
Total area — length × depth in square feet. Used for screw rates and as a quick sanity check.
Decking boards — the number of boards to buy at the lumber yard, including waste for your chosen pattern. Always buy this many — short cuts require full boards.
Decking linear ft — the raw linear footage of decking needed before waste. Useful if you're pricing by the lineal foot.
Joists — the framing boards that run under the deck. Your lumber yard will cut them to your deck depth (or buy pre-cut).
Framing linear ft — total lumber needed for joists + ledger + beam + rim joists. Bring this number to the yard; the size (2×8, 2×10) is determined by your span.
Footings — the number of concrete column forms to dig and pour. One post per footing, spaced every 8 ft along the outer beam.
Concrete bags — 50-lb bags (Quikrete or similar) at 2 bags per footing. Adjust if your tube forms are larger than 10".
Deck screws — #10 × 3" coated screws, with a 5% buffer for drops and stripped heads. Rates: 350/100 sq ft at 16" OC, 470 at 12", 235 at 24".
Hidden clips — one clip per board-joist intersection. Composite fastener systems (Camo, Ipe Clip, etc.) use one clip or bracket at every point where a board crosses a joist.
Plan View
Top-down · Not to structural scale
Shopping List
Enter your deck dimensions to generate a shopping list.
Important: These quantities are estimates. Footing depth, beam sizing, and joist spans must be confirmed against your local building codes. Consult a licensed contractor before purchasing materials. See our deck code reference and permit guide.
Related Calculators
Methodology
How the calculator works.
Decking boards
Rows = ⌈ (depth × 12) ÷ (board width + gap) ⌉. The 1/8" gap (or 1/4" for composite) prevents water trapping and allows for expansion. Waste: 10% perpendicular, 15% diagonal, 20% herringbone. Board count = ⌈ linear feet ÷ board length ⌉.
Framing lumber
Joist count = ⌈ (length × 12) ÷ spacing ⌉ + 1 — ceiling ensures an end rim joist even when the length is not an exact multiple. Total framing LF = joist LF + ledger (1×length) + beam (1×length) + 2 rim joists (1×depth each).
Footings & concrete
Footing count = ⌈ length ÷ 8 ft ⌉ + 1 — one footing every 8 ft along the outer beam plus one at each end. Concrete = 2 bags (50 lb) per footing for a standard 10" tube form.
Fasteners
Wood: screw count at 16" OC = 350/100 sq ft × area × 1.05 buffer. 12" OC = 470, 24" OC = 235.
Composite: hidden clips = rows × joist count — one clip per board-joist intersection, which is how composite fastener systems (Camo, Ipe Clip, etc.) are designed.
Board size reference
| Nominal | Actual width | Best use |
|---|---|---|
| 5/4×6 | 5.5" | Most popular decking, lighter than 2×6 |
| 2×6 | 5.5" | Stronger feel underfoot, same coverage as 5/4×6 |
| 2×4 | 3.5" | More board-to-board gaps, classic look |
| Composite 5/4×6 | 5.5" | Trex, TimberTech, Fiberon — use composite preset |
FAQ
Frequently asked questions.
How many deck boards do I need?
Divide your deck depth in inches by the board width plus the gap (typically 1/8"). Round up to get the number of rows, multiply rows × deck length to get linear feet, add your waste factor (10% perpendicular, 15% diagonal, 20% herringbone), then divide by your board length and round up. This calculator does all that math instantly.
What is a laying pattern and how much extra do I need?
Perpendicular (boards run parallel to the house) is the most common and adds 10% waste for end cuts. Diagonal 45° adds 15% because boards have angled cuts at every end. Herringbone or chevron patterns add 20% because every board is cut at an angle with no reuse of offcuts.
What joist spacing should I use?
16" on center is the most common residential spacing and works for 5/4×6 and 2×6 decking. Use 12" OC for 2×4 boards or heavier loads. 24" OC is acceptable only for 2×6 boards in low-load situations — confirm with your local building department.
What is the difference between wood and composite decking?
Wood boards (5/4×6, 2×6, pressure-treated) use screws driven through the top face. Composite boards (like Trex) are typically 1" thick × 5.5" wide and use hidden fastener clips at each board-joist intersection. Composite requires wider board gaps (1/4" vs 1/8") to allow for expansion.
How much concrete do I need per footing?
Two 50-lb bags per footing is standard for a 10-inch diameter tube form. For larger footings or deeper frost lines, you'll need more. Your local building department specifies minimum footing dimensions.
How far apart should deck footings be?
One footing every 8 feet along the beam is a common starting point for residential decks. This calculator uses that guideline. Your beam span table, soil bearing capacity, and local code will set the final spacing.
Can I bookmark this page and come back to my numbers?
Yes — every input is saved in the page URL. Just bookmark it or copy the URL from your browser's address bar. Share the link with anyone and they'll see the exact same calculation.
Do I need a permit to build a deck?
Most jurisdictions require a permit for attached decks or any deck over 200 sq ft or 30" above grade. Always verify with your local building department. See our deck permit guide for more on the process.