How Many Deck Boards for a Large 24x20 ft Deck?
A 24×20 ft deck with 5.5-inch boards and 15% waste allowance requires approximately 55 deck boards.
How to use this tool
- Enter the deck length and width in feet.
- Enter the actual face width of your decking boards in inches.
- Set the gap size (typically 1/4 in) and a 10% waste factor.
- The calculator returns total area and number of boards to buy.
Calculate deck board quantities for a large 24×20 foot deck with extra waste allowance for angle cuts and complex patterns.
Frequently asked questions
- How many deck boards do I need?
- Divide the deck width by (board width + gap) to get the number of rows, then multiply by the deck length to see total board linear footage. Add 10% for waste.
- What is the standard gap between deck boards?
- A 1/4-inch gap between boards is standard for composite and pressure-treated lumber. This allows drainage and accounts for wood expansion.