SPI (Stitches Per Inch)

Definition

The number of stitches in one inch of seam — a key quality specification in garment manufacturing. Higher SPI creates stronger, tighter seams but slows production. Typical SPI ranges: 8-10 for overlock seams on knitwear, 10-12 for woven garment seams, and 4-7 for decorative topstitching. SPI is checked during inline quality inspection and must match the tech pack specification within +/- 1 stitch.