Deck Square Footage Calculator

L × W = deck area. For decking material order, see deck-material.

Inputs

Result

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How to use this calculator

  • Enter deck dimensions.
  • For irregular shapes, use square-footage-irregular.

About this calculator

A simple square-footage variant for deck planning. For multi-level or irregular decks, sum the rectangles. Use deck-material for board, joist, post counts.

Frequently asked

Multi-level decks?+
Sum the area of each level (level 1 + level 2). They share posts at junctions but each level is its own surface.
Including stairs?+
Optional — stair landings add ~12-20 ft² each. Stairs themselves don't typically count as "deck area".
Cost per square foot?+
Pressure-treated: $20-30/ft² installed. Cedar: $30-40. Composite: $40-60. Ipe and other premiums: $50-80+.
Permit threshold?+
Many areas require permits for decks > 30" off ground. Check local code.
Maximum recommended size?+
No max, but balance is ~deck area = 12-20% of indoor square footage. Bigger decks need bigger plans.

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