18×18 Deck Cost Calculator: 2026 Price Guide

18×18 deck costs between $6,480 and $21,060 for most homeowners in 2026, depending on material and location. At 324 square feet, it is a large square deck that provides ample space for full outdoor living including dining, lounging, and entertaining.

Frequently Asked Questions

How much does an 18×18 deck cost in 2026?

An 18×18 deck costs between $6,480 and $11,340 for pressure-treated wood and $11,340 to $21,060 for composite decking. At 324 square feet it is a substantial build that significantly enhances outdoor living space.

What can fit on an 18×18 deck?

An 18×18 deck comfortably fits a large dining table for 8, a full outdoor sofa set, a grill station, and still has room for potted plants and movement. Many homeowners add a pergola or shade structure at this size.

Is an 18×18 a common deck size?

It is less common than 16×16 or 20×20 but a great square option for homeowners who want more space than a 16×16 without going all the way to 400 square feet. The square shape also works well for certain yard configurations.

How long does it take to build an 18×18 deck?

An 18×18 deck typically takes 6 to 10 days for an experienced crew. Permit approval, site preparation, and custom features can extend the timeline.