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18x12 Pergolas

We offer a wide selection of 18x12 pergola kits, including both free-standing and house-attached kits, those with shade canopies and those made for a slatted wood roof, and some made for smaller 4x4 wood frames and others for larger 6x6s. Use the filtering options below to quickly find the perfect 2-block pergola kit for your outdoor space.

  SIMILAR SIZES:  12x18 pergolas  |  16x12 pergolas  |  18x10 pergolas  |  20x12 pergolas
  • Attached 18x12 Pergola Off House with Roof (6 Options) - Kit for 4x4 Wood

    Original price Starting at $499
    Original price Starting at $499
    Original price $499
    Starting at $399
    Starting at $499 $399
    Current price $399
    Original price $499
    20% Off

  • Freestanding 18x12 Pergola Kit with Roof (6 Options) - Kit for 4x4 Wood

    Original price Starting at $749
    Original price Starting at $749
    Original price $749
    Starting at $599
    Starting at $749 $599
    Current price $599
    Original price $749
    20% Off

  • Wall-Mounted 18' x 12' Pergola with Shade Covers - Kit for 4x4 Wood

    Original price $949
    Original price Starting at $949
    Original price $949
    Current price $759
    Original price $949
    Starting at $949 $759
    Current price $759
    Original price $949
    20% Off

  • 18' x 12' Pergola Attached to House with Roof (6 Options) - Kit for 6x6 Wood

    Original price Starting at $999
    Original price Starting at $999
    Original price $999
    Starting at $799
    Starting at $999 $799
    Current price $799
    Original price $999
    20% Off

  • Stand-Alone 18 x 12 Pergola with Canopies - Kit for 4x4 Wood

    Original price $1,199
    Original price Starting at $1,199
    Original price $1,199
    Current price $959
    Original price $1,199
    Starting at $1,199 $959
    Current price $959
    Original price $1,199
    20% Off

  • Attached 18 by 12 Pergola and Canopies - Kit for 6x6 Wood

    Original price $1,429
    Original price Starting at $1,429
    Original price $1,429
    Current price $1,129
    Original price $1,429
    Starting at $1,429 $1,129
    Current price $1,129
    Original price $1,429
    21% Off

  • Free-Standing 18' x 12' Pergola with Roof (6 Options) - Kit for 6x6 Wood

    Original price Starting at $1,499
    Original price Starting at $1,499
    Original price $1,499
    Starting at $1,199
    Starting at $1,499 $1,199
    Current price $1,199
    Original price $1,499
    20% Off

  • 18x12 Covered Pergola with Sun Shades - Kit for 6x6 Wood

    Original price $1,949
    Original price Starting at $1,949
    Original price $1,949
    Current price $1,559
    Original price $1,949
    Starting at $1,949 $1,559
    Current price $1,559
    Original price $1,949
    20% Off

18x12 Refers to the Combined Inner Dimensions of the 2 Roof Openings

When we say a pergola's dimensions are 18x12, we are referring to the combined inside dimensions of the 2 roof openings (inside-edge to inside-edge). All of the kits featured on this page are meant to have 2 roof openings that are both 12' deep and which combine to be a total of 18' wide. (Note: If you choose a kit made for a slatted wood roof, the combined width of the 2 roof openings can be divided any way you'd like: both 9' deep or one 9.5' and one 8.5' deep or one 10' and one 8' deep or any other combination that adds up to 18 feet.)

The overall outside-edge to outside-edge dimensions of the pergola will be:

With all of this being said, you can easily change the overall size of your pergola by trimming the wood posts that you plan to use for the roof beams. For example, if you wanted the true outside-edge to outside-edge dimensions of a free-standing pergola to be exactly 18' x 12', you would need to:

  • Purchase two sets of two posts totaling 18 feet to be the beams running the 18-foot width, and then cut off a total of 14.6 inches (for 4x4 wood posts) or 22.6 inches (for 6x6 wood posts) per set of two posts; and
  • Purchase three 12-foot posts to be the beams running the 12-foot depth, and then cut off 7.3 inches (for 4x4 wood posts) or 11.3 inches (for 6x6 wood posts) from each one

Important Note: Our shade canopies are specifically designed to fit roof openings that are exactly 8x8, 8x10, 8x12, 10x10, 10x12 and 12x12. If you're purchasing a kit with shade canopies, you cannot trim down the roof beam posts. Furthermore, all roof posts must be 8-, 10- or 12-foot lengths.

Reminder: Width & Depth Are Not Always Interchangeable

18' x 12' pergolas are different from 12' x 18' pergolas. The wall-mounted pergolas on this page will attach to your home on the 18' width side and come 12' out from the house wall. For free-standing pergolas with a slatted roof, the roof rafters will be mounted to the 12' beams and run the 18-foot width of the pergola (providing more shade when the afternoon/evening sunlight comes from the 18-foot width side). If your afternoon/evening sunlight will come from the 12-foot side, you'll want a 12x18 pergola instead.