How it works
Use the result as a checked starting point.
Square footage alone does not tell you how many boards to buy. Actual board width, spacing, stock length, running direction, seams, and waste determine the takeoff.
This calculator assumes full stock boards are used across each row and rounds every cut requirement up. A planned stagger or efficient reuse of offcuts may change the final count.
Rows = deck width ÷ (board width + gap). Boards per row = deck length ÷ stock length.
Estimating checks
- Confirm actual—not nominal—board width.
- Plan seam locations around joist layout and manufacturer requirements.
- Calculate fascia, stairs, picture framing, blocking, and structure separately.
Common questions
Does this include framing lumber?
No. It covers deck boards and the entered fastener/extras allowance.
Can offcuts reduce the board count?
Sometimes. This estimator is intentionally conservative and does not optimize a cut list.
What gap should I use?
Follow the decking manufacturer’s installation guidance and account for material movement and site conditions.