The Basics
A pattern repeat is the distance from the starting point of a design on the fabric to the place where that design starts over again, repeating itself. For example, if the repeat is 12 inches and includes a flower along the edge, the top of that flower will be at the same position every 12 inches along the edge.

The pattern repeat is listed on the fabric sample tag when fabric is ordered from a sample book or a fabric retailer. When purchasing the fabric off a bolt, simply measure from one specific point in the pattern to where it occurs again. A common pattern repeat is 27 inches, but pattern repeats can be as little as 2 or 3 inches and larger than 36 inches.

When making a window treatment or other project that uses wide widths of fabric, such as the projects above, it's critical to allow enough fabric for the pattern repeat so the design will continue uninterrupted when pieces of fabric are sewn side by side. For example, if half of a vase is on one selvage of the fabric, the other half of the vase will be on the other selvage. When the two pieces are sewn together, the vase is complete. Most printed fabrics are designed this way.

For professional-looking results, always match patterns. This goes for multiple window treatments in a room, as well as within the same window treatment. From window to window in a room the motifs should match, or fall at the same height, on every treatment.

To allow for pattern repeat on a window treatment, you have to know how much fabric to buy. First, determine the length of fabric you will need for each piece, including the header and the hem. Then, use the pattern repeat formula explained in "Figuring Pattern Repeats" and "Figuring a Drop Pattern," on pages 3 and 4, to determine how much extra fabric is needed to match the design in every cut. The same rules apply for other projects that require sewing fabrics side by side.