Deck calculator
| Group | Cost |
|---|---|
| Framing | $417 |
| Decking | $381 |
| Guards and stairs | $548 |
| Hardware | $865 |
| Concrete | $281 |
| Total | $2,491 |
| Size | Length | Qty | Used for |
|---|---|---|---|
| 1x8 | 8 ft | 1 | Stair risers |
| 1x8 | 12 ft | 1 | Stair risers |
| 2x10 | 16 ft | 2 | Beam plies |
| 2x12 | 8 ft | 1 | Stair stringers |
| 2x12 | 12 ft | 1 | Stair stringers |
| 2x4 | 10 ft | 1 | Guard rails |
| 2x4 | 12 ft | 4 | Guard rails |
| 2x4 | 16 ft | 3 | Guard rails, Stair bearing blocks, Handrail |
| 2x6 | 10 ft | 1 | Guard cap |
| 2x6 | 12 ft | 2 | Guard cap |
| 2x6 | 14 ft | 1 | Guard cap |
| 2x8 | 12 ft | 13 | Joists |
| 2x8 | 16 ft | 2 | Rim joist, Ledger |
| 4x4 | 16 ft | 3 | Stair posts, Guard posts |
| 5/4x6 | 10 ft | 1 | Stair treads |
| 5/4x6 | 16 ft | 27 | Decking, Stair treads |
| 6x6 | 8 ft | 1 | Posts |
| Item | Qty | What to look for |
|---|---|---|
| Joist hanger, 2x8, at the ledger | 13 ea | face-mount, >= 500 lb, depth >= 60% of the ledger, galvanized |
| Hurricane tie, joist to beam B1 | 13 ea | >= 100 lb uplift and lateral (DCA6 Figure 6, Option 2) |
| Post base, 6x6 | 3 ea | galvanized standoff post base, anchored in the footing |
| Post cap, 6x6 post to 2-ply 2x10 beam | 3 ea | galvanized post cap sized to the beam width (required for 3-ply) |
| 1/2 in x 4 in lag screw with washer | 12 ea | hot-dip galvanized; tip fully past the inside of the band; 1/2 in pilot in the ledger, 5/16 in in the band |
| Ledger flashing, 10 ft | 2 ea | continuous corrosion-resistant metal >= 0.019 in with drip edge; no aluminum on copper-treated lumber |
| Lateral load hold-down device | 2 ea | >= 1,500 lb ASD, within 24 in of each deck end, into house joists or blocking |
| Baluster, 2x2 x 36 in, pressure-treated | 96 ea | 3-1/2 in clear between balusters (4 in sphere rule), 2 screws each end |
| Guard post hold-down | 10 ea | >= 1,800 lb tension for a 36 in guard, at the top bolt, (8) SDS1/4x1-1/2 screws into 2x blocking (DCA6 Figure 25/26) |
| 1/2 in through-bolt, nut and 2 washers, guard posts | 20 ea | two per guard post through the joist or rim |
| Deck screw, coated or stainless, #8 or #10 | 724 ea | 2 per board per joist (or 2 threaded 8d nails) |
| Connector nails or screws | 260 ea | the type and count each connector maker lists; never fewer |
| Structural screw, rim to joist ends | 39 ea | 3 per joist end through the rim |
| Stringer connector at the rim | 3 ea | galvanized stringer hanger or angle (DCA6 Figure 31) |
| #8 wood screw, stringer to bearing block | 21 ea | 7 per stringer in Southern Pine, 11 in other species (DCA6 Commentary C12) |
| 1/2 in through-bolt, nut and 2 washers, stair posts | 4 ea | two per stair post |
| Concrete mix, 80 lb bag | 28 bag | 2,500 psi minimum |
| Concrete tube form, 12 in x 4 ft | 5 ea | pier from the footing to 2 in above grade |
| Table | Row | Column | Allowed | Yours |
|---|---|---|---|---|
| DCA 6 Table 2 | Southern Pine 2x8 | 16 in o.c. | 11'-10" | 9'-10 1/2" |
| DCA 6 Table 2 overhang | Southern Pine 2x8 | 16 in o.c. | 2'-0" | 2'-0" |
| DCA 6 Table 3A | Southern Pine 2-2x10 | joists <= 10 ft | 7'-9" | 7'-0" |
| DCA 6 Table 4 | beam span <= 8 ft, joists <= 10 ft | Southern Pine 6x6 | 14'-0" | 1'-6 1/2" |
| DCA 6 Table 5 | 1/2 in lag screw, 1-1/2 in lumber band | joist span 8'-1" to 10'-0" | 18 in | 16.727272727272727 in |
| DCA 6 Table 4 footing | beam span <= 8 ft, joists <= 10 ft | 1,500 psf soil | 20 in | 20 in |
What the deck calculator counts
It sizes the frame first, then counts what it takes to build it. The joists, beam, posts and footings come from the AWC DCA 6 tables, so the list is for a deck that follows the guide. Then it adds the decking, the hanger and tie hardware, the post bases and caps, and the bags of concrete. Stairs and guards are counted when you switch them on.
How the boards are cut
Lumber is bought in fixed lengths, and the calculator packs each cut onto the shortest board that holds it. The list you see is what you would carry out of the yard, not the raw footage. A saw kerf is allowed for between cuts.
Prices
Cost uses shelf prices read at The Home Depot, Hamilton Mill, on 2026-09-30. Prices differ by store and week.
Our cost to build a deck guide prices four standard sizes in wood and composite and sets them beside the installed ranges the cost sites publish.
What it does not count
Lights, permits, tools, delivery, sales tax, and any site work or digging. Treat the count as the starting point for your shopping list and ask the yard for an extra board or two for mistakes.
Where the numbers come from
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Questions
Anything else? Write to us or see every calculator.
Questions people ask
We do not quote labor, because it swings with the region, the height and the contractor. Our calculator counts the materials, so you can price the same list from your lumber yard and hold any contractor's bid up against it. If you hire out the build, ask for materials and labor as separate lines.
The decking and the frame are the two big lines, and which is bigger depends on the boards you pick. For a 16 by 12 ft deck at 36 in, our count is 27 decking boards and 38 boards of framing and other lumber, before hardware and concrete. Switch the decking above between wood and composite to see how the count and the boards change, then price each line at your own yard.
Divide the length of the deck, measured across the boards, by the board width plus the gap, which is 5.5 in plus about 1/8 in for wood, to get the number of rows. Then cover each row with boards from the lengths the yard sells, 8, 10, 12 or 16 ft, so the cuts waste as little as possible. The calculator does this packing for every board in the deck, joists and beam included.
Yes. It counts the ledger, joists, beam, posts, the concrete for the footings, joist hangers, post bases and the fasteners. Stairs are optional, and guard rails are added on their own once the deck is more than 30 in above grade. Boards are bought in 8, 10, 12, 16 ft lengths, and longer special-order boards only where a piece cannot be spliced.