DCA6-2015 sizing · the in-app takeoff engine
Deck material calculator
Your deck
Placeholder until your building department gives you the frost depth.
Applied to every line except the board count, which already carries its own.
The pile in the driveway — counted, not priced
192 sq ft
29 distinct line items, every one counted by the engine
No prices here on purpose: lumber moves weekly and by region, and a materials number without labour, permits, access and margin reads like a quote while meaning nothing. The count is what keeps an order honest — the price belongs to your contractor and their supplier.
Deck boards
29
461 lf
Joists
15
72 lf of rim
Posts / footings
4
49 bags of concrete
Hidden clips
400
112 face screws
DeckingBoards, fascia & deck fasteners6 items
| Item | Qty | Unit |
|---|---|---|
| Composite Deck Board — Grooved field, 5.5" × 16' (waste incl.) | 25 | ea |
| Composite Deck Board — Square-edge perimeter / picture frame, 5.5" × 16' (waste incl.) | 4 | ea |
| Fascia / Rim Trim — 1×12 × 12' | 4 | ea |
+3 more items — a free contractor trial prices this whole job; the full order sheet, at your supplier costs and exportable, comes with a plan.
SubstructureJoists, beams, posts, hangers & footings — full framing takeoff16 items
| Item | Qty | Unit |
|---|---|---|
| 2x10 Pressure-Treated Joist @ 16" OC × 12' run | 15 | ea |
| Rim Joist — 2x10 PT × 16' (covers 72 lf) | 5 | ea |
| Joist Blocking — 2x10 PT × 16' (covers 16 lf) | 1 | ea |
+13 more items — a free contractor trial prices this whole job; the full order sheet, at your supplier costs and exportable, comes with a plan.
RailingsRail sections, posts & connectors3 items
| Item | Qty | Unit |
|---|---|---|
| Aluminum Railing — 6' section | 8 | ea |
| Railing Posts | 10 | ea |
+1 more item — a free contractor trial prices this whole job; the full order sheet, at your supplier costs and exportable, comes with a plan.
StairsStringers, treads, risers & landing pads4 items
| Item | Qty | Unit |
|---|---|---|
| Stair Stringers — 2x12 PT × 8' (5 per 48" flight @ ~12" o.c. — composite treads; 5 risers) | 5 | ea |
| Stair Treads — Composite 12" × 10.5" | 4 | ea |
+2 more items — a free contractor trial prices this whole job; the full order sheet, at your supplier costs and exportable, comes with a plan.
Quantities are the engine's, not a rule of thumb: board counts carry their own waste (plus a diagonal bonus on 45° layouts), hidden clips are counted per square foot of grooved field and bought by the bucket, ledger bolts are spaced off the DCA6 Table 5 lookup, and concrete is bagged from the real pier volume. Prices are yours.
Counted, not squared off
Most deck material calculators multiply square footage by a coverage factor and add ten percent. That gets you a decking number and nothing else — no frame, no hardware, no concrete, which is most of what the truck actually delivers.
This one runs the same takeoff engine that builds order sheets inside the DeckPro app. It sizes the structure first — joist section, beam size and post count are screened against the AWC DCA 6-2015 span tables for the deck you entered — and then counts what that structure takes: the 16' × 12' deck it opens with comes back as 29 separate line items. Hangers are counted per joist end, clips per square foot of grooved decking, concrete per footing at your footing depth, rail sections per side that needs a guard.
Quantities are the whole story here, deliberately. Prices are your supplier's, and a materials subtotal pretending to be a build cost is how homeowners and contractors end up arguing over a number neither of them believes.
What the list covers
Decking — field boards and the fascia, laid by direction, with waste. Framing — 15 joists, 1 beam line and 4 posts for the opening deck, every member sized before it is counted. Hardware — 15 joist hangers plus post bases and ledger fasteners. Concrete — 49 80 lb bags for the footings at the default 3-foot depth; set your local frost depth and the count follows. Fasteners — 400 hidden clips at 2.4 per square foot, plus face screws and framing nails. Railing and stairs — 36 linear feet of guard on the open sides, and a 48" stair with 4 treads on 5 cut stringers.
Every count updates live as you change the deck — and if a dimension pushes a member past what the prescriptive tables allow, the engine says so instead of quietly counting something unbuildable.
Common questions
How many deck boards do I need for a 16x12 deck?
29 boards — 461 linear feet of decking — for the 16' × 12' composite deck this page opens with (192 sq ft), with the opening 10% waste allowance included. The count is honest area math rounded up to whole boards: your waste percentage feeds it directly, boards run at 45 degrees add 15% to it, and a picture-frame border changes the parts mix — square-edge border boards and perimeter blocking — rather than the count. Resize the deck above and read the number that comes back.
What materials do I need to build a deck?
Seven buckets, and a complete list touches all of them: decking and fascia; the frame (joists, beams, posts); joist hangers and structural hardware; footings and concrete; fasteners (hidden clips or face screws, plus framing nails); railing; and stairs. For the 16' × 12' deck above, that comes to 29 distinct line items — 29 deck boards, 15 2x10 joists at 16" on center, 15 hangers, 4 posts, and 49 bags of concrete among them.
Does a deck material calculator include the framing?
Most do not — they cover the surface and leave the structure to you, which is half the order. This one counts the frame the same way it counts boards, and sizes it first: joists, beams and posts are screened against the AWC DCA 6-2015 span tables for the deck you entered, then counted. The 16' × 12' deck above frames with 15 2x10 joists on 1 beam line, carried by 4 posts on 4 footings.
How much extra decking should I order for waste?
The calculator starts at 10%, which covers straight-run cutoffs and culls on a rectangular deck, and the waste field above feeds the board count directly — raise it for complex outlines and short spans and watch the count move. Boards run at 45 degrees add 15% on top of whatever you set, because every field board gets an angled cut at both ends.
How many hidden fasteners do I need?
Figure 2.4 clips per square foot of grooved decking. The 16' × 12' deck above takes 400 clips, and they sell by the bucket of 90 — the calculator counts the clips and the order sheet inside the app rounds to whole buckets, because that is how the store sells them.
Why does this calculator not show prices?
Because a materials number without labor, permits and site conditions reads like a quote while meaning nothing. Lumber and composite prices are also local — they are your supplier costs, not a national average. Quantities are the part that is knowable from the design alone, so that is what this page gives you. Inside DeckPro, the same engine prices the sheet at a contractor’s own supplier costs; the free trial shows the priced totals with a preview of the sheet, and the full line-item order sheet comes with a plan.
Sizing one member instead of counting the whole deck? Start with the joist span calculator or the beam and footing calculator.
Keep going
Joist span calculator
How far a 2x6, 2x8, 2x10 or 2x12 deck joist spans at 12", 16" or 24" on center — plus the overhang the same cell allows.
DCA6-2015 Table 2, p.4
Beam & footing calculator
Beam size, post spacing and footing diameter for one deck — including the post/footing combinations the table marks Not Permitted.
DCA6-2015 Table 3A + Table 4 · IRC R507
Deck stair calculator
Riser height, tread depth, stringer count and cut layout, screened against IRC R311.7 — including the 3/8" riser uniformity rule.
IRC R311.7 · R312.1
Ledger fastener spacing
On-center spacing for ½" lags and through-bolts in a deck ledger, by the joist span it carries and the band joist behind it.
DCA6-2015 Table 5, p.15
Now do the whole deck
The calculator sizes one member. The free designer runs the same tables across a real footprint — every joist, beam, post and footing sized together, with the full material list underneath. No signup.
Source & limits
AWC DCA 6-2015, Prescriptive Residential Wood Deck Construction Guide (based on the 2015 IRC), © 2018 American Wood Council. The guide is published free by AWC.
Estimate only — not an engineered design. Spans, sizes, and quantities are screened against the AWC DCA 6-2015 / IRC prescriptive baseline at 40 psf live + 10 psf dead load. Local codes and amendments vary; your Authority Having Jurisdiction (AHJ) and a licensed design professional govern. Verify everything with a permit and a licensed pro before ordering or building.