Shrinkage

Shrinkage measures how much a garment pulls in from its as-cut dimensions after laundering, and heat is the main driver: hot water in the wash and high heat in the dryer do most of the damage. Untreated 100% cotton can lose 5% or more in both length and width after the first several wash-and-dry cycles, which on a 28-inch body length adds up to well over an inch disappearing off the hem.

Gildan lists roughly 4 to 5% residual shrinkage on its Heavy Cotton 5000 line even after mill preshrinking, and Comfort Colors' garment-dyed cotton can shrink further still, since the dyeing process itself relaxes the fibers before that final finishing wash. That's a meaningful gap between what a spec sheet promises and what a customer feels after they've washed the shirt a few times.

On any non-preshrunk or garment-dyed blank, pros size a run up rather than trusting the flat measurement, or they pull the vendor's residual shrinkage percentage off the spec sheet and build it into the size chart before cutting the order, especially for a client who wants a true-to-size, snug fit out of the dryer.

The mistake buyers make is assuming preshrunk means a garment won't shrink at all. Preshrunk, or sanforized, cotton is compacted at the mill to hold shrinkage to roughly 3% or less, not zero, so a preshrunk tee can still tighten noticeably over its first several washes, especially with repeated hot-water cycles and machine drying instead of a cold wash and a hang-dry.