Decking & Lumber Calculators
Decking and lumber calculators figure board counts, joist spacing, and board feet for deck and framing projects.
Beam Deflection CalculatorBeam Load CalculatorBoard Foot CalculatorCantilever Beam Deflection CalculatorComposite Decking CalculatorCord of Wood CalculatorDeck Joist CalculatorDeck Load CalculatorDeck Stain CalculatorDecking Board CalculatorFirewood CalculatorFraming CalculatorI Beam Weight CalculatorJoist Spacing CalculatorLumber Weight CalculatorOSB CalculatorPlywood CalculatorRafter CalculatorStair CalculatorStair Stringer CalculatorStud Calculator
Frequently asked questions
How many deck boards cover one square foot?
A standard 5.5-inch-wide board covers 0.458 sq ft per linear foot, so a 12-ft board covers 5.5 sq ft. Our decking calculator uses that figure; adjust if your boards are a different width or length.
What joist spacing does composite decking need?
Most composite brands require 16-inch on-center joists for perpendicular installs and 12-inch for diagonal patterns — tighter than the 24-inch spacing some wood decks use. Check your specific product before framing.
Should deck boards run parallel or diagonal to the house?
Perpendicular to the joists is structural; the visual direction is your choice. Diagonal layouts look sharp but add 10-15% cutting waste and require tighter joist spacing — budget for both.