Deck Board Calculator
Enter the deck size and board details to see how many deck boards and screws to order.
Results are estimates for planning only. Always confirm measurements, local codes and manufacturer specs before ordering materials or quoting a job. See our Terms.
How to calculate deck boards
Rows of boards = deck width (in) / (board width + gap). Multiply rows by the deck length to get linear feet, add waste, then divide by the board length you are buying.
A "5/4 x 6" wood board or most composite boards are actually about 5.5 inches wide. Typical gaps are 1/8 to 1/4 inch. Two screws per board at every joist is standard; composite boards often use hidden fasteners instead.
Questions
How many deck boards do I need for a 12 x 16 deck?
With 5.5 inch boards and a 3/16 inch gap running the 16 ft way, about 26 rows, or 29 boards of 16 ft with 10% waste.
How many screws per deck board?
Two screws at each joist. On a 16 ft board over 16 inch joists, that is about 26 screws per board.
Which way should deck boards run?
Usually perpendicular to the joists and parallel to the house. Diagonal layouts need closer joist spacing and about 15% more material.