Yarn Lot Calculator — Same Dye Lot Planning

A dye lot is a batch of yarn dyed at the same time in the same dye bath. Even with precise recipes, there are always tiny colour variations between dye lots. These differences may be invisible when comparing single balls but become obvious as stripes or bands when knitted together. Always buy enough from the same dye lot for your entire project.

Check the ball band for the dye lot number (sometimes labelled "lot" or "batch"). All balls with the same lot number were dyed together and should match perfectly. Some hand-dyed and undyed yarns may not have lot numbers; for hand-dyed yarn, buy enough at once from the same batch.

If you must use two dye lots, alternate balls every 2 rows across the transition zone. This gradually blends the colours rather than creating a visible line. Start alternating about 5cm before the old lot runs out. This technique works well for most projects.

Most dyed yarns have dye lots. Some solid acrylics (like Stylecraft Special DK, Red Heart Super Saver and Caron Simply Soft) are labelled "no dye lot", meaning colour matching is usually very consistent between batches. In practice even no-dye-lot solids can still drift slightly between separate purchases, so buying everything at once remains the safest option. Undyed natural yarns and some tonal/variegated yarns may also skip lot numbers. When in doubt, buy enough at once.