basic

Deck Board Quantity & Joist Spacing Calculator

Board count from deck area, board size, and gap.

Calculates how many deck boards are needed for a rectangular deck from deck dimensions, board width, gap, and board length, including a waste allowance.

10 of 10 free calculations left today. Sign up for more.
Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
Was this helpful?

How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Boards = ceil(deck_width / (board_width + gap)) × deck_length / board_length × (1 + waste)

In depth

Calculates how many deck boards are needed for a rectangular deck from deck dimensions, board width, gap, and board length, including a waste allowance.