ContractorHandbook

How Many Boards for a 16x16 Deck?

Deck boards to buy

34 16 ft boards

256 square feet, 34 rows of full length 16 foot boards, joists 16 inches on center.

It does not stop at a number.

When the figures look right, the deck material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.

boardgap betweenboardsdeck width, ftwidth / (board + gap) = rows, rows x length = linear feet
Decking is bought in linear feet and laid in rows, and the gap between boards is what sets how many rows fit. A quarter inch gap across a twelve foot width is most of an extra board, which is the difference between one trip and two.

How that number is worked out

These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.

  • Deck length16 ft
  • Deck width16 ft
  • Board face width5.5 in
  • Gap between boards0.25 in
  • Board length you buy16 ft
  • Joist spacing on center16 in

Deck boards to buy34 16 ft boards

Deck area256 sq ft
Board rows across the width34
Linear feet of decking544 lf
Boards at 16 ft34
Joists at 16 in on center13

The material list this produces

Deck boards, 16 ft34
Joists, 16 ft13
Joist hangers, each26
Deck screws, lb8

Board length compared

Same deck, four board lengths. Longer boards mean fewer end joints and more offcut risk.

Board lengthDeck boards to buy
8 ft boards68 8 ft boards
12 ft boards46 12 ft boards
16 ft boards34 16 ft boards
20 ft boards28 20 ft boards

What else matters here

This is the size where the numbers land perfectly: 34 rows across 16 feet, every row a single 16 foot board, no joints and almost no offcut. It is the reason 16 by 16 is such a common deck size, and it is worth knowing before you talk yourself into 15 by 17.

Thirteen joists at 16 inch centers span the width. At 16 feet a 2x8 is at or past its limit for most species at that spacing, so this is usually a 2x10 deck rather than a 2x8 one. Check the span table rather than matching whatever the neighbor used.

Beam and footing sizing is the other thing that changes at this size. A 256 square foot deck carries real load, and the beam that supports thirteen 16 foot joists is not the beam that supported a 12 by 12.

What this calculator assumes

  • A nominal 2x6 board is 5.5 inches of actual face. Nominal sizes are not real sizes, which is where most deck orders go wrong.
  • Joist count is the span across the deck width at the spacing given, plus one for the last joist.
  • Waste is not added. Add 5 to 10 percent if the deck is not a plain rectangle.

Questions people ask

How many deck boards for a 16x16 deck?

About 34 boards of 5/4 by 6 at 16 feet, one full board per row with no butt joints.

What joist size for a 16 foot span?

Usually 2x10 at 16 inches on center for common decking species, but the exact answer is in your code's span table for the species, grade and spacing you are using.

How far apart should deck footings be?

It depends on beam size and joist span, not on a fixed number. The beam span table in the residential code sets it, and a 16 by 16 deck usually lands between six and eight feet.

Different numbers?

The deck calculator takes any dimensions you like and hands back the same list.

Other common sizes