Most of shirts are knitted by using large single circular knitting machine which is similar to sock knitting machine while the size is much larger. Knitting machines with various standard sizes knit the shirts into a tube shape. Single circular knitting machine can vary colors and types of yarns quickly and cheaply.
After tubes being knitted, the neck, hem, shoulders and sleeve are cut. The method is quite economical and uses few fabrics. It makes shirts cheaper. Thicker interlock, double knits and fashion pattern knits are knitted on flat knitting machine. There fabrics are cut out similar to all other garments and have a wide seam. The prices of fabrics are quit high and more fabrics are wasted in cutting. T-shirts with style details, fitting details or body shaping are cut with seams so they details can be added or so the fit is better.
