Decking Calculator
Our decking calculator is the efficient way to understand material quantity for your next decking installation. Simply pop in the dimensions of the area you want decked, and our handy calculator will give you an accurate number of decking boards for the job. Whether composite or timber, our UK decking calculator takes the guesswork out of any deck project.
Enter decking board size
Width, mm
x
Length, mm
x
Measure your area(s)
Area 1
Width, m
x
Length, m
x
=
Thermal Expansion & Gapping: Composite and timber boards expand and contract with the weather. Boards must be spaced slightly apart. The calculator usually assumes a standard gap (like 3/16"), but the actual installation spacing affects how many boards are needed. Framing and Joists: A calculator can estimate joists based on standard 16-inch or 12-inch spacing. However, stairs, picture-frame borders, and heavy loads (like hot tubs) require extra structural framing that standard calculators can't predict. Estimate only.