Decking Calculator
Estimate how many deck boards (and linear feet) you need for a deck.
Find out how many deck boards you need, including the gap between boards and a waste allowance for cuts.
How the Math Works
The Decking Calculator uses the formula (boardWidth + gap)/12 × boardLength to determine the coverage area of each deck board. This calculation converts the board width and gap from inches to feet (divided by 12), then multiplies by the board's length in feet to compute how much area one board covers. By dividing the total deck area by this coverage value, you determine the number of boards needed. The linear feet required are simply the number of boards multiplied by the board length, accounting for gaps and spacing.
Practical Applications
To use this calculator, first measure your deck's total area (length × width). Input the width of your deck boards, the desired gap between boards, and the length of each board. The calculator applies the formula to estimate how many boards you'll need and the total linear footage required, factoring in spacing and waste. This ensures you purchase the correct quantity without running short or overbuying materials.
Day-to-Day Use
This tool simplifies deck planning by providing precise material estimates quickly. Instead of manually calculating and risking errors, you can confidently order the exact number of boards and linear feet needed, saving time and money. It also helps avoid common project delays caused by material shortages, making DIY deck projects more efficient and stress-free for homeowners.
Worked example
16×12 ft deck (192 ft²), 5.5 in boards, 1/8 in gap, 16 ft long → coverage 7.5 ft² → 26 boards with 10% waste.
FAQ
What gap should deck boards have?
1/8 in for pre-dried boards; up to 1/4 in for wet/treated boards that will shrink.