When a mill quotes a plush fleece, you will see two sets of numbers that matter more than any others: the GSM (the fabric weight) and the shrinkage (how much the fabric moves after washing). Get either one wrong and you end up with a blanket that feels paper-thin or a pet bed cover that no longer fits its insert after the first wash. Here is what each number actually means, how the industry tests them, and what to write into your order so there is no argument later.
GSM — the fabric's weight, not its thickness
GSM stands for grams per square meter; it is the standard way the industry quotes fabric weight. It is not the same as thickness — a lofty, brushed fleece can feel thick yet weigh less than a denser, shorter-pile knit. Weight is what drives cost, warmth and hand feel, so it is the first spec a factory needs.
As a general scale for fleece: lightweight runs roughly 100–200 GSM, midweight around 200–300 GSM, and heavyweight at 300 GSM or more. Heavy polar fleece commonly sits in the 280–330 g/m² range, where you notice more loft and warmth but also more bulk at the seams. The Fabric Company's fleece-by-the-yard guide breaks down these weight bands and how each feels at the cutting table.
Which GSM to spec for plush and pet products
Weight should follow end use, not habit. A good starting point for the products we make:
- 150–180 GSM — light throws and quilt backings; low bulk, easy to sew and fold.
- 200–250 GSM — the sweet spot for everyday polar/coral fleece and pet blankets; warm without being heavy.
- 250–300 GSM — heavier fleece throws and robes with more substance and drape.
- 300+ GSM — structured pet beds, premium winter blankets and thick linings that need to hold shape.
The single most common sourcing mistake is quoting a GSM that sounds "safe" without a hand-feel sample. GSM alone tells you nothing about nap, density or how the pile brushes — always pair the number with a physical swatch before you commit to bulk.
Shrinkage — why fleece moves in the wash
Fabric shrinks because it is held under tension the entire time it is made. Yarn is spun under tension, knitted under tension, and stretched through dyeing and finishing. The first wash is the first chance the structure gets to relax — water, heat and agitation release that locked-in tension, and the fabric snaps back toward the relaxed state it wanted all along. That contraction is shrinkage.
Because the mechanism is stored tension, the direction pulled hardest shrinks the most. In knits that is usually the length (wale) direction. This is why a real shrinkage report always lists length and width separately — a single averaged number hides a lot of risk. And it is why a knit that shrinks 5% in length can grow slightly in width at the same time.
How shrinkage is tested (and what the report should say)
Shrinkage is not a feeling — it is a measured number from a defined procedure. The industry-standard method is: condition and mark a specimen, wash and dry it per a ISO 6330 (or AATCC 135/150) program, then re-measure the marked points and report the dimensional change per ISO 5077. The formula is (original − final) ÷ original × 100, run separately for length and width.
Two details separate a real test from a reassuring one. First, the fabric should be sampled from the bulk production lot, not a pristine lab dip — the roll you cut is the one that matters. Second, the wash program must reflect how your customer actually launders the product. Tumble drying pulls out the most shrinkage; line drying the least. If your test line-dries but your customer tumble-dries, the test lied to you.
What is an acceptable shrinkage number?
Commercial acceptance limits differ by construction because knits carry far more stored tension than wovens do. As industry benchmarks: wovens are held to roughly ±2–3%, and knits to around ±5% in length and width. Our own guidance for loose-fill throws and pet blankets: shrinkage at or below about 4.5–5.0% after home laundering.
Demand a spec line that reads: "Max shrinkage ≤ 5% length and ≤ 5% width, tested to ISO 6330 / ISO 5077, program [washing + drying], on the bulk lot." Naming the standard and the wash program removes the most common cross-border dispute: two parties quoting numbers from different wash conditions.
What the mill does to keep shrinkage low
Good finishing controls shrinkage before the fabric ever reaches your cutting table. For synthetics like polyester fleece, the key step is heat setting (a thermal process that relaxes the thermoplastic fibers and locks in dimensional stability) plus compacting / sanforizing, a mechanical preshrinking that physically pre-releases tension in the knit loops. A mill that skips these steps ships a fabric that shrinks on the customer's first wash — which is exactly why the shrinkage report matters more than a soft hand feel.
Putting the two numbers together in your order brief
When you request a fleece quote, the brief costs nothing to write and saves a lot of rework:
- Fabric + GSM — e.g. "Coral fleece, 240 GSM, 200 cm width."
- End use — throw, pet bed, robe or apparel; different uses change the weight you should spec.
- Shrinkage limit — "≤5% length and width, ISO 6330/AATCC 135 home-launder."
- A physical swatch — always confirm hand feel and nap before bulk.
Plush fleece dyeing and finishing typically starts around 100–200 kg per color; for smaller needs, ask about our stock and small-batch options.
References
- The Fabric Company — How to Choose Fleece Fabric by the Yard (GSM weight bands, polar fleece 280–330 g/m², fleece shrinkage guidance).
- Gibben Clothing — Fabric Shrinkage, Spirality & Colorfastness Explained (shrinkage mechanism, knit vs woven tolerance, ISO 6330/5077 test procedure, heat setting & compacting).
- KARCEM — Textile Test Standards Reference (ISO/AATCC/ASTM shrinkage and weight test standards, typical knit acceptance ±3–5%).