To determine how many deck boards you need for a 10×10, 12×12, and 16×16 deck, you’ll first need to calculate the total square footage of each deck size and then divide that by the square footage of the deck boards you plan to use.

Assuming you are using standard 5.5-inch wide deck boards, you can use the following calculations:

For a 10×10 deck (100 square feet), you would need approximately 18 deck boards (100 sq. ft. / 5.5 sq. ft. per board = 18.18, round up to 19 boards to account for waste).

For a 12×12 deck (144 square feet), you would need approximately 26 deck boards (144 sq. ft. / 5.5 sq. ft. per board = 26.18, round up to 27 boards for waste).

For a 16×16 deck (256 square feet), you would need approximately 47 deck boards (256 sq. ft. / 5.5 sq. ft. per board = 46.55, round up to 47 boards for waste).

Decking material makes up the deck subflooring and is available in a variety of styles, lengths and widths. Whether you’re building a wood deck or composite deck, you’ll need to know the width of the decking boards. As an example, 5/4 x 6 pressure treated decking measures actual size 5/4″ thick and 5 1/2 inches wide.

The lumber which are used as subfloor for any size deck is measured in board unit. The 2×6 or 5/4 ×6 nominal size of lumber used as board. The spaced between two board are 1/8″ apart. One standard board comes in 5/4″ thick, 5.5″ width and length of 10′, 12′, 16′ & 20 foot.

**How many deck boards do i need for any deck**

To figure the number of deck boards you will need for your build any deck, take the area (square footage) of your deck and divide that number by the one deck board area (square footage. For eg, a 10 by 10 deck will give you 100 square feet for the deck’s square footage and one deck board will you 4.58 square feet for the board square footage. So, number of deck boards = 100/4.58 = 22 deck boards.

**Or second methods:**

To figure the number of deck boards you will need for your build any deck, divide the width of deck in inches by width of one deck board. Generally a deck board is 5.5″ wide. For eg, a 8×10 deck measures 8 feet wide, convert it into inches and then divide by 5.5″, i.e (8 ×12)/ 5.5 = 18 deck boards needed.

How many boards you will need for any deck, divide the square footage of deck by square footage of one board. If you have deck measures 10×10, then square footage of deck = 10×10 = 100 square feet and square footage of one deck board =( 5.5× 10 )/12 = 4.58 square feet, no. of deck boards = 100/ 4.58 = 22 boards. Thus, you would need 22 nos of 5/4″×6″×10′ size of boards for a 10×10 deck.

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**How to calculate how many deck boards do i need for a 10×10 deck**

**Step 1:** Determine the square footage of deck board i.e, for a deck that is 10 feet long and 10 feet wide, multiply 10 by 10. This gives you 100 square feet, that is deck’s total area.

**Step 2:-** Decide which board length to use, for a 10×10 deck, you can use deck board that is 10 feet long, 5/4″ thick and 5.5″ width, represented as nominal size of 5/4″×6″×10′.

**Step 3:-** Determine board square footage, if you have choosen deck board that is 10 feet long by 5.5″ wide, convert 5.5″ into feet i.e 5.5/12 = 0.458 feet, multiply 0.458 by 10. This gives 4.58 square feet that is one deck board area.

**Step 4:-** Divide deck square footage by board square footage, you have total area of deck is 100 sq ft and one board area is 4.58 square feet, so, number of deck boards you will need = 100/ 4.58 = 22 boards.

**Step 5:-** Determine deck board spacing, distance between two board is 1/8″ or 0.125″, so use the formula to calculate total boards spacing = 0.125 × (n -2), 0.125 × (22-2) = 2.5 inches.

**Step 6:-** Determine deck board spacing square footage, multiply total spacing in feet by length of deck board, (2.5″×10′)/ 12 = 2.08 square feet

If the square footage of board spacing is more than one boards’ square footage, you may be able to skip purchasing an extra board or two. In this example, 2.08 square feet is less than one board’s square footage, 4.58 square feet, so you’ll still stick with 22 boards to carry into Step 6.

**Step 7:-** Add 10% for mishaps, waste and off cuts, so, 10% of 22 boards = 2.2, add this 22 + 2.2 = 24.2, round as whole number 25 boards.

You would need 22 (twenty two) 10 feet long deck boards for a 10×10 deck. You’ll need a space of ⅛” between each board. However, we would always advise you do your calculations carefully yourself before buying.

For a 10×10 square deck, you would need **22 (twenty two)** 10′ deck boards. Always add 10% for mishaps, waste and off cuts. The most common dimension of board is a 5/4” thick by 6” wide deck board of any length.

**How many deck boards do i need for a 8×10 deck**

If your floating or attached deck is 8×10 foot with deck boards which spaced 1/8″ apart will require **18 (eighteen) 10 feet** long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 20 boards.

**Maths calculation:-** 1) Square footage of deck = 8×10 = 80 square feet, 2) Square footage of one board = (5.5 ×10)/ 12 = 4.58 boards, 3) no. of deck boards = 80/ 4.58 = 17.45, round to 18 boards, 4) add 10% extra, i.e 18 + 1.8 = 19.8, round as 20 boards.

**How many deck boards do i need for a 12×12 deck**

If your floating or attached deck is 12×12 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 12 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×12 = 144 square feet, 2) Square footage of one board = (5.5 ×12)/ 12 = 5.5 boards, 3) no. of deck boards = 144/ 5.5 = 26.18, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many deck boards do i need for a 12×18 deck**

If your floating or attached deck is 12×18 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 18 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×18 = 216 square feet, 2) Square footage of one board = (5.5 ×18)/ 12 = 8.25 boards, 3) no. of deck boards = 216/ 8.25 = 26.18, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many deck boards do i need for a 12×16 deck**

If your floating or attached deck is 12×16 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 16 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×16 = 192 square feet, 2) Square footage of one board = (5.5 ×16)/ 12 = 7.33 boards, 3) no. of deck boards = 192/ 7.33 = 26.19, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many deck boards do i need for a 10×12 deck**

If your floating or attached deck is 10×12 foot with deck boards which spaced 1/8″ apart will require **22 (twenty two)** 12 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 25 boards.

**Maths calculation:-** 1) Square footage of deck = 10×12 = 120 square feet, 2) Square footage of one board = (5.5 ×12)/ 12 = 5.5 boards, 3) no. of deck boards = 120/ 5.5 = 21.81, round to 22 boards, 4) add 10% extra, i.e 22 + 2.2 = 24.2, round as 25 boards.

**How many deck boards do i need for a 8×8 deck**

If your floating or attached deck is 8×8 foot with deck boards which spaced 1/8″ apart will require **18 (eighteen)** 8 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 20 boards.

**Maths calculation:-** 1) Square footage of deck = 8×8 = 64 square feet, 2) Square footage of one board = (5.5 ×8)/ 12 = 3.66 boards, 3) no. of deck boards = 64/ 3.66 = 17.48, round to 18 boards, 4) add 10% extra, i.e 18 + 1.8 = 19.8, round as 20 boards.

**How many deck boards do i need for a 8×16 deck**

If your floating or attached deck is 8×16 foot with deck boards which spaced 1/8″ apart will require **18 (eighteen)** 16 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 20 boards.

**Maths calculation:-** 1) Square footage of deck = 8×16 = 128 square feet, 2) Square footage of one board = (5.5 ×16)/ 12 = 7.33 boards, 3) no. of deck boards = 128/ 7.33 = 17.46, round to 18 boards, 4) add 10% extra, i.e 18 + 1.8 = 19.8, round as 20 boards.

**How many deck boards do i need for a 8×12 deck**

If your floating or attached deck is 8×12 foot with deck boards which spaced 1/8″ apart will require **18 (eighteen)** 12 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 20 boards.

**Maths calculation:-** 1) Square footage of deck = 8×12 = 96 square feet, 2) Square footage of one board = (5.5 ×12)/ 12 = 5.5 boards, 3) no. of deck boards = 96/ 5.5 = 17.45, round to 18 boards, 4) add 10% extra, i.e 18 + 1.8 = 19.8, round as 20 boards.

**How many deck boards do i need for a 10×16 deck**

If your floating or attached deck is 10×16 foot with deck boards which spaced 1/8″ apart will require **22 (twenty two)**16 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 25 boards.

**Maths calculation:-** 1) Square footage of deck = 10×16 = 160 square feet, 2) Square footage of one board = (5.5 ×16)/ 12 = 7.33 boards, 3) no. of deck boards = 160/ 7.33 = 21.82, round to 22 boards, 4) add 10% extra, i.e 22 + 2.2 = 24.2, round as 25 boards.

**How many deck boards do i need for a 10×20 deck**

If your floating or attached deck is 10×20 foot with deck boards which spaced 1/8″ apart will require **22 (twenty two)** 20 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 25 boards.

**Maths calculation:-** 1) Square footage of deck = 10×20 = 200 square feet, 2) Square footage of one board = (5.5 ×20)/ 12 = 9.16 boards, 3) no. of deck boards = 200/ 9.16 = 21.83, round to 22 boards, 4) add 10% extra, i.e 22 + 2.2 = 24.2, round as 25 boards.

**How many deck boards do i need for a 12×14 deck**

If your floating or attached deck is 12×14 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 14 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×14 = 168 square feet, 2) Square footage of one board = (5.5 ×14)/ 12 = 6.41 boards, 3) no. of deck boards = 168/ 6.41 = 26.20, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many deck boards do i need for a 14×14 deck**

If your floating or attached deck is 14×14 foot with deck boards which spaced 1/8″ apart will require **31 (thirty one)** 14 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 35 boards.

**Maths calculation:-** 1) Square footage of deck = 14×14 = 196 square feet, 2) Square footage of one board = (5.5 ×14)/ 12 = 6.41 boards, 3) no. of deck boards = 196/ 6.41 = 30.57, round to 31 boards, 4) add 10% extra, i.e 31 + 3.1 = 34.1, round as 35 boards.

**How many deck boards do i need for a 16×16 deck**

If your floating or attached deck is 16×16 foot with deck boards which spaced 1/8″ apart will require **35 (thirty five)** 16 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 39 boards.

**Maths calculation:-** 1) Square footage of deck = 16×16 = 256 square feet, 2) Square footage of one board = (5.5 ×16)/ 12 = 7.33 boards, 3) no. of deck boards = 256/ 7.33 = 34.92, round to 35 boards, 4) add 10% extra, i.e 35 + 3.5 = 38.5, round as 39 boards.

**How many deck boards do i need for a 16×20 deck**

If your floating or attached deck is 16×20 foot with deck boards which spaced 1/8″ apart will require **35 (thirty five)** 20 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 39 boards.

**Maths calculation:-** 1) Square footage of deck = 16×20 = 320 square feet, 2) Square footage of one board = (5.5 ×20)/ 12 = 9.16 boards, 3) no. of deck boards = 320/ 9.16 = 34.93, round to 35 boards, 4) add 10% extra, i.e 35 + 3.5 = 38.5, round as 39 boards.

**How many deck boards do i need for a 20×20 deck**

If your floating or attached deck is 20×20 foot with deck boards which spaced 1/8″ apart will require **44 (forty four)** 20 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 49 boards.

**Maths calculation:-** 1) Square footage of deck = 20×20 = 400 square feet, 2) Square footage of one board = (5.5 ×20)/ 12 = 9.16 boards, 3) no. of deck boards = 400/ 9.16 = 43.66, round to 44 boards, 4) add 10% extra, i.e 44 + 4.4 = 48.4, round as 49 boards.

**How many deck boards do i need for a 12×20 deck**

If your floating or attached deck is 12×20 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 20 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×20 = 240 square feet, 2) Square footage of one board = (5.5 ×20)/ 12 = 9.16 boards, 3) no. of deck boards = 240/ 9.16 = 26.20, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many deck boards do i need for a 12×24 deck**

If your floating or attached deck is 12×24 foot with deck boards which spaced 1/8″ apart will require **27 (twenty seven)** 24 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 30 boards.

**Maths calculation:-** 1) Square footage of deck = 12×24 = 288 square feet, 2) Square footage of one board = (5.5 ×24)/ 12 = 11 boards, 3) no. of deck boards = 288/ 11 = 26.18, round to 27 boards, 4) add 10% extra, i.e 27 + 2.7 = 29.7, round as 30 boards.

**How many steps for a 3′, 4′, 5′ and 6 foot high deck**

**What is the maximum span for a 2×6, 2×8, 2×10 & 2×12 deck joist**

**Conclusions:**

If your floating or attached deck is 10×10 foot with deck boards which spaced 1/8″ apart will require 22 (twenty two) 10 feet long deck boards. Always buy 10% extra for mishaps, so, sum of total you would need therefore 25 boards.

For a 10×10 square deck, you would therefore need twenty-two 10 feet long deck boards. To figure the number of deck boards you will need for any deck, take the area of your deck and divide that number by the one deck board area.