Deck Calculator

Deck boards, joists and screws for a rectangular deck.

Runs in your browser — nothing is uploaded
Units

—

Material estimates only — add waste, confirm quantities with your supplier and follow local building codes. Not an engineering guarantee.

How to use Deck Calculator

  1. Enter your values — the unit for each field is shown next to it.
  2. The result updates instantly as you type.
  3. Copy the results, or change inputs to compare scenarios.

Formula & assumptions

Rows = ⌈deck width ÷ (board width + gap)⌉; boards = ⌈rows × deck length × (1 + waste) ÷ board length⌉