How decking quantity is estimated
Board width plus spacing determines the effective width of each row. Dividing deck width by that effective width estimates how many rows are required.
Deck material example
For a 20-foot by 12-foot deck, the number of board rows depends on the actual board width and spacing between boards.
This calculator estimates surface decking only. Joists, beams, posts, footings, fasteners, stairs and railings are not included.
Frequently asked questions
What does linear feet mean?
Linear feet measures total board length rather than surface area.
Does board spacing matter?
Yes. Larger gaps slightly reduce the number of rows needed.
Does this calculator include framing?
No. It estimates decking surface material only.
Using this calculator effectively
This calculator estimates deck-board rows and total linear feet from deck dimensions, board width and gap. It is useful for surface-decking quantity and does not attempt to design the supporting frame.
Common uses
- Estimating decking-board linear footage.
- Comparing board widths and gap sizes.
- Adding a waste allowance for trimming and board selection.
Tips for a better estimate
- Use the actual installed board width rather than only a nominal lumber size.
- Include the intended gap between boards in the layout calculation.
- Plan framing, stairs, fascia and special patterns separately from the deck-surface estimate.
Related calculations
Linear Feet Calculator · Cubic Feet Calculator · Fence Calculator