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Calculation Machine

Deck Calculator

Boards, joists and cost for a deck.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Deck boards (16 ft)
28
Board rows
26
Joists at 16 in centres
13
Deck area
192 sq ft
Estimated board cost
$504.00

Quick answer

Deck board count depends on deck area, board width and the gap between boards, plus joists at 16 inch centres.

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Deck length16 ft
  • Deck width12 ft
  • Board width5.5 inches
  • Gap between boards0.25 inches
  • Price per board18 $

Result

  • Deck boards (16 ft)28
  • Board rows26
  • Joists at 16 in centres13
  • Deck area192 sq ft
  • Estimated board cost$504.00

How to use the Deck Calculator

  1. 1Enter your deck dimensions.
  2. 2Enter board width and spacing gap.
  3. 3Add 5% for cuts and defects.

Frequently asked questions

What gap should I leave?

1/8 to 1/4 inch for pressure-treated boards that will shrink as they dry.

How deep are footings?

Below your local frost line — often 36–48 inches in cold climates.

About this calculator