Joists
13 @ 12 ft + ledger/rim: 2 × 16 ft
EstimateYard · Deck materials list · estimateyard.com
Decks & lumber · materials
Deck materials calculator — boards, joists & fasteners
A deck’s bill of materials comes from two numbers: board rows across the width (5.5-in board + ¼-in gap) and joists every 16 in along the length. A 12 × 16 ft deck takes 29 boards, 13 joists, and ~680 screws. Enter your size for the full list and August 2026 cost ranges.
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Your materials list 12 × 16 ft · 16″ OC
29boards
@ 16 ft (458 lineal ft incl. 10% waste)
Fasteners
676 screws (2 per crossing — or the same count of hidden clips for grooved composite)
Deck area
192 sq ft
Installed cost range
$2,880–$6,720 pressure-treated, installed (deck surface + framing; railings/stairs extra)
Counts cover the walking surface and its joists. Beams, posts, footings, railings, and stairs depend on height and layout — and joist/beam sizing is a local-code span-table question, not a calculator question.
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Common deck sizes, worked out
All rows: 16-in joist spacing, boards run the long dimension, 10% board waste.
| Deck | Deck boards | Joists | Screws | |
|---|---|---|---|---|
| 10 × 10 ft | 24 @ 10 ft | 9 @ 10 ft | ≈380 | Open › |
| 10 × 12 ft | 24 @ 12 ft | 10 @ 10 ft | ≈420 | Open › |
| 12 × 12 ft | 29 @ 12 ft | 10 @ 12 ft | ≈520 | Open › |
| 12 × 16 ft | 29 @ 16 ft | 13 @ 12 ft | ≈680 | Open › |
| 12 × 20 ft | 29 @ 20 ft | 16 @ 12 ft | ≈830 | Open › |
| 16 × 20 ft | 38 @ 20 ft | 16 @ 16 ft | ≈1,090 | Open › |
How this calculator works
Prices updated August 2026Boards: rows = width ÷ 5.75 in (5.5-in actual board + ¼-in gap), rounded up; count = rows × 1.10 waste, as boards the length of the deck. Joists: (length × 12 ÷ spacing) + 1, each spanning the width; ledger and rim call for 2 × length of matching stock. Screws: rows × joists × 2. Costs: installed ranges — pressure-treated $15–$35/sq ft (typical market estimate), composite $35–$70/sq ft (2026 cited; composite boards alone run $4–$16/sq ft in materials). Source: HomeGuide 2026 composite decking data. Framing sizes are governed by local code span tables.
Common questions
How many deck boards do I need for a 12×16 deck?
With standard 5.5-in boards and a ¼-in gap, a 12 ft-wide deck takes 26 board rows; at 16 ft long with 10% waste that is 29 sixteen-foot boards (≈460 lineal feet). Running boards the long way looks best and minimizes butt joints.
How far apart do deck joists go?
16 inches on-center is standard for wood decking laid perpendicular. Most composite brands also allow 16 in for perpendicular boards but require 12 in for diagonal layouts — check your board’s span chart, and your local code for joist sizing.
How many screws does a deck take?
Two per board at every joist crossing — roughly 3.5 screws per square foot at 16-in spacing. A 12×16 deck (192 sq ft) needs ~680 deck screws, or the same count of hidden clips for grooved composite boards.
How much does a deck cost in 2026?
Installed: pressure-treated wood roughly $15–$35/sq ft; composite $35–$70/sq ft. A 12×16 deck: ~$2.9k–$6.7k in wood, $6.7k–$13k in composite. Railings, stairs, and height add real money beyond these base ranges.
What size joists does a deck need?
Commonly 2×8s for spans up to ~12 ft at 16-in spacing, 2×10s beyond — but joist sizing is governed by species, grade, and your local code’s span tables. This calculator counts joists; a permit drawing sizes them.