Shrinkage feels like a defect. It’s physics: yarn is spun and knitted under tension, and the first hot wash lets the fabric relax to the size it always wanted to be. The whole trick is making that relaxation happen at the mill instead of in your customer’s machine, then writing the number into your spec.
What normal looks like
- Untreated cotton jersey: 5–10% shrinkage, front-loaded into the first wash, enough to drop a size.
- Compacted cotton: ±3–5%, the standard commercial tolerance, tested after three home launderings.
- Cotton-poly blends: less again, polyester’s stability anchors the fabric. <a href="/blog/cotton-cvc-poly-cotton-tshirt-fabric-blends/">The blends guide.</a>
- Length vs width: knits shrink more in length; a garment that “got shorter and boxier” shrank exactly as physics predicts.
Compacting: the process that earns “pre-shrunk”
At finishing, the fabric is steamed and mechanically overfed so its loops compress into their relaxed geometry, shrinkage spent before cutting. It’s also what keeps a printed logo from distorting after wash one, and printed-panel garments aligned. A factory that can’t tell you whether its fabric is compacted is telling you something.
The three lines for your tech pack
- Shrinkage tolerance: ±5% maximum after 3 washes (±3% for premium programmes), method stated (home laundering, 40°C).
- Twist/spirality limit for single jersey, the sibling problem to shrinkage. <a href="/blog/single-jersey-vs-interlock-vs-pique/">Constructions explained.</a>
- Wash-test the PP sample yourself before approval, one domestic wash answers everything. <a href="/blog/garment-sample-approval-checklist/">The approval checklist.</a>
Our knit fabrics are compacted as standard and specced with written tolerances — ask for the numbers with your quote.