Deck Calculator
Use this deck calculator to estimate deck area and approximate decking board length.
How to Use the Deck Calculator
Enter deck length, width, board dimensions and spacing to estimate deck area and board quantity.
Practical Example
A 6 m by 4 m deck covers 24 m². Board width, gaps and cutting waste determine how many boards are needed.
Factors That Affect the Result
Board orientation, spacing, joist layout, stairs, borders, picture framing, offcuts and damaged boards can change the final quantity.
Frequently Asked Questions
Should I add waste?
Yes. Extra boards help cover cuts and defects.
Does board spacing matter?
Yes. Gaps affect the number of boards across the deck.
Can I use this for composite decking?
Yes, using the actual board dimensions.
Related Tools
Deck Material Planning
Enter the deck length and width to estimate the surface area, then use board width and spacing to plan decking quantities. Gaps between boards, board direction, picture-frame borders and cutoffs can change the final count, so include a practical waste allowance. This estimate focuses on the deck surface; joists, beams, posts, footings, fasteners and railings should be calculated separately. Round up to full board lengths and consider the available stock sizes before purchasing material.