Easy Wood Calc

How many deck boards for a 12×16 deck?

Short answer

A 12 × 16 ft deck needs 29 boards of 18 ft decking — 26 rows of 5½ in boards running the long way, plus 10% waste — and about 676 screws across 13 joists. With a 1 inch overhang at each end every row is 194 in (16 ft 2 in), so 16 ft boards are too short.

How to work it out

  1. (144 in + 3/16 in gap) ÷ (5-1/2 in + 3/16 in) = 25.35 → 26 rows
  2. Each row = 192 in + 2 × 1 in overhang = 194 in (16 ft 2 in)
  3. One row from each 18 ft board → 26 boards × 1.1 waste = 29 boards
  4. 192 in ÷ 16 in spacing, rounded up, + 1 = 13 joists
  5. 13 joists × 26 rows × 2 = 676 screws

Running boards along the 16 ft side means one board per row — but a row is 16 ft 2 in once each end overhangs the frame by an inch, so 16 ft stock won’t reach. Buy 18s, frame the deck 2 in shorter, or plan butt joints. If the boards instead run across the 12 ft width, you need 34 rows of 14 ft boards — the table and the variants below compare the options.

Adjust for your project

ft
Boards usually run parallel to the house, so this is usually the side along the house. Measure the frame, outside to outside.
ft
in
Often 1/8–1/4 in; follow the board maker
in
How far the boards run past the rim or fascia at each end. About 1 in is common; 0 if you trim them flush.
in
On center = middle of one joist to the middle of the next. Most decks: 16.
More options: Border · Waste allowance
A border board around all four edges, mitered at the corners. The field boards then run between the end border boards.
%
Deck boards to buy29 boards18 ft
Rows of boards
26 rows
Each row, end to end (with overhangs)
194 in (16 ft 2 in)
Linear length of decking
420 ft
Face screws (2 per joist)
676 screws
Or hidden clips (≈1 per board per joist)
338 clips
Joists the boards cross
13 joists
Deck area
192 sq ft
  • Each board leaves an offcut. If a shorter stock length still covers a row with its overhangs, buying that length may be cheaper.
  • Hidden fastener counts are a rough guide — check the clip maker’s coverage chart, which also covers start and end clips.
Check your codeCode limits vary by jurisdiction — confirm with your building department before you cut or build. (IRC R507.7)

For this job · affiliate link
Exterior deck screwsAbout 700 screws — buy them in bulk tubs rather than small boxes, rated for treated lumber (or the composite maker’s own screws).
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Boards by stock length (12 × 16 ft deck)

Boards by stock length (12 × 16 ft deck)
Board lengthDeck boards to buyLinear length of decking
8 ft58 boards420 ft
10 ft47 boards420 ft
12 ft39 boards420 ft
16 ft29 boards420 ft
18 ft29 boards420 ft
20 ft29 boards420 ft

What to know about decking a 12x16 deck

  • Boards along the 16 ft side need more than 16 ft of stock. 18 ft boards give one board per row with no joints; 16 ft boards leave every row 2 in short. Long boards are heavy and awkward — plan delivery, and have a second person to carry them. A picture-frame border is the other way out: the field boards shrink to 15 ft 2-5/8 in and 16 ft boards fit them, though the two long border boards still need 18s.
  • Joists run the short way. With boards parallel to the house on a 16 ft ledger, the joists run out 12 ft and usually span 10 to 11 ft to a beam. Size them with How far can a 2x10 deck joist span and its 2×8 companion.
  • About 676 screws. Thirteen joists at 16 in on center, 26 rows, two screws per crossing. At 12 in spacing — common under composite — it rises to 17 joists.
  • Metric stock is shorter still. A 4.8 m board is about 3 in shorter than 16 ft, and even 4.88 m (16 ft) stock can’t cover a 16 ft 2 in row. Pick 5.4 m stock, or add a breaker board.

For a smaller square deck, the same method is worked through in How many deck boards for a 12x12 deck.

Different size? Use the full Deck Board Calculator.

What you’ll need

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Frequently asked questions

How many deck boards for a 12x16 deck with boards running the 12 ft way?

38 boards of 14 ft decking with 10% waste — 34 rows across the 16 ft side, each 146 in (12 ft 2 in) with the overhangs — and about 680 screws.

Can I use 16 ft deck boards on a 16 ft deck?

Only if you trim them flush with the frame. With a 1 inch overhang at each end each row is 194 in (16 ft 2 in), so every row would need a butt joint over a doubled joist and a filler piece long enough to reach the next joist. Buy 18 ft boards instead, or frame the deck 2 in shorter.

How many deck screws for a 12x16 deck at 12 in joist spacing?

About 884 screws — 17 joists × 26 rows × 2 screws, with boards running the 16 ft length.

How many 7 1/4 in deck boards for a 12x16 deck?

22 boards of 18 ft, 7¼ in (2×8) boards with 10% waste — 20 rows across the 12 ft width.

Other common sizes

Sources