A yarn label packs several independent pieces of information into a small space, and each one answers a different question a knitter or crocheter needs before starting a project. Reading it correctly avoids surprises later.
Weight category symbol
A numbered icon (typically 0 through 7) shows where the yarn falls in the standard weight system, matching the yarn weight system guide. This is a fast way to confirm a substitute yarn is in the right general range before checking anything more specific.
Yardage and weight
Listed as a length (yards or meters) paired with a weight (grams or ounces), this pair is what feeds directly into yardage planning and yarn substitution math. Two skeins with the same weight category can carry different yardage-per-gram, which is exactly the ratio that matters for a substitution to behave like the original, covered in how to substitute yarn without ruining gauge.
Dye lot
A batch number specific to the vat or run the yarn was dyed in. Skeins from different dye lots, even in the identical colorway, can show a visible shade difference once knit up side by side. For any project using more than one skein, buying all skeins from the same dye lot, or planning color-blending rows near a lot change, avoids a visible seam of mismatched shade partway through the piece.
Recommended gauge and needle or hook size
The manufacturer's suggested starting point, not a guaranteed outcome. Personal tension varies enough that this number is where you start swatching, not where you stop, per the reasoning in common gauge mistakes and how to fix them.
Care symbols
Standard laundry-style icons show washing, drying, ironing, and bleaching guidance specific to the fiber content. These matter most for gift projects and anything intended for frequent washing, since fiber content alone (see acrylic vs. wool vs. blend yarn) doesn't always predict a specific yarn's exact care requirements, particularly for treated fibers like superwash wool.
Fiber content percentage
Listed by weight percentage (for example, 80% wool, 20% nylon), this tells you what to expect for warmth, durability, and stretch, and it's the number that explains why two yarns in the same weight category can feel and perform so differently.