ContractorHandbook

How Many Boards for an 8x10 Deck?

Deck boards to buy

9 20 ft boards

80 square feet, 17 rows running the 10 foot way, 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 length10 ft
  • Deck width8 ft
  • Board face width5.5 in
  • Gap between boards0.25 in
  • Board length you buy20 ft
  • Joist spacing on center16 in

Deck boards to buy9 20 ft boards

Deck area80 sq ft
Board rows across the width17
Linear feet of decking170 lf
Boards at 20 ft9
Joists at 16 in on center9

The material list this produces

Deck boards, 20 ft9
Joists, 8 ft9
Joist hangers, each18
Deck screws, lb3

Board length compared

Same deck, four board lengths.

Board lengthDeck boards to buy
8 ft boards22 8 ft boards
12 ft boards15 12 ft boards
16 ft boards11 16 ft boards
20 ft boards9 20 ft boards

What else matters here

Seventeen rows at 10 feet, 170 linear feet, nine 20 foot boards cut in half. Nine boards to carry instead of seventeen, and every row a single unbroken piece.

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 boards for an 8x10 deck?

Nine boards of 5/4 by 6 at 20 feet cut in half, or seventeen at 10 feet, both giving 170 linear feet.

How many joists for an 8x10 deck?

Nine at 16 inches on center along the 10 foot run, each one 8 feet long.

Different numbers?

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

Other common sizes

4x4 deck5 8 ft boards4x6 deck5 12 ft boards5x5 deck7 8 ft boards4x8 deck9 8 ft boards6x6 deck7 12 ft boards6x8 deck13 8 ft boards6x10 deck11 12 ft boards8x8 deck9 16 ft boards8x12 deck17 12 ft boards10x10 deck11 20 ft boards10x12 deck21 12 ft boards12x12 deck20 16 ft boards12x16 deck26 16 ft boards10x20 deck21 20 ft boards12x20 deck33 16 ft boards16x16 deck34 16 ft boards12x24 deck52 12 ft boards16x20 deck43 16 ft boards16x24 deck51 16 ft boards20x20 deck42 20 ft boards20x30 deck63 20 ft boards

Contractor Handbook · https://contractorhandbook.com/calculators/deck-calculator/8x10-deck/