Pattern Matching Calculator

The goal of pattern matching is to make seam lines disappear into the print. When horizontal stripes or plaid bars align perfectly across a side seam, the garment looks intentional and polished. When they do not match, the eye is drawn to every seam.

Prioritize matching at the most visible seams first: side seams at the hip and bust, center front and center back, and sleeve-to-bodice at the front armhole notch. Less visible seams (underarm, inside leg) are lower priority.

To match at seams, lay the pattern pieces on a single layer of fabric (not folded). Position each piece so the same bar or motif falls at the same distance from the seam line. Use transparent rulers and mark the match points directly on the pattern tissue.

Fabrics with a nap (velvet, corduroy, brushed flannel) or a one-way print (flowers growing upward, animals facing one direction) require all pattern pieces to be cut in the same direction. This is called a “with nap” layout.

A with-nap layout typically uses 10 to 20 percent more fabric than a standard layout because you cannot flip pieces head-to-tail to interlock them on the cutting table.

Most pattern envelopes list separate yardage for “with nap” and “without nap.” If your fabric has both a repeat and a nap, use the with-nap yardage as your base, then add the extra from this calculator on top of that.

For plaids and large checks, center the dominant vertical bar on the center front and center back grainlines. This creates visual symmetry even before you worry about matching at seams.

Check whether your plaid is even or uneven. An even plaid mirrors both vertically and horizontally — fold the fabric in half along a dominant bar and the pattern should overlay exactly. An uneven plaid does not mirror in one or both directions.

Even plaids are far easier to work with. For uneven plaids, cut all pieces in a single layer and mark the “up” direction on every piece. You may also need to flip the pattern tissue for left and right sides rather than cutting on the fold.

Plaid matching is the single biggest consumer of extra fabric. Budget one full repeat per piece in both directions for a complex garment, and buy a quarter to half yard (or quarter metre) extra as insurance.