Cotton, Polyester or Blend: Choosing Knit Fabric

No single blend is best. The composition line is a trade between hand feel, dimensional stability, moisture behaviour and stretch recovery, and the right answer is the one that matches how the garment is washed and worn, not the highest cotton percentage. Write the percentages, the yarn and the weight, and the fabric can be sourced and checked against them.

Why is a blend a trade between four properties?

A knit can be soft, stable, absorbent or elastic, and raising one usually lowers another. Softness costs stability; stability costs hand feel; cotton absorbs moisture and then dries slowly; recovery comes from elastane, which ages with heat. The composition line decides which of the four the garment cannot afford to lose.

What does each direction give you, and what does it cost?

Read the third column before the second, because the cost is what you live with after the first wash. The bands we quote most often are 240–550 gsm on hoodies and 220–280 gsm on leggings.

Fibre or blend	What it gives	What it costs	Fits
100% cotton	Soft hand, takes dye and print cleanly, absorbs moisture and feels cool	Shrinks and creases unless pre-shrunk, dries slowly, neckline relaxes	Tees, polos and hoodies where cotton reads as quality
Cotton-polyester	Holds its measurements through washing, dries faster, smooth at low weight	Pills where the two fibres abrade, static in dry air, flatter in the hand	Uniforms, team kits, promotional programmes
Polyester performance	Wicks moisture to the surface, light for the warmth it holds, holds colour	Holds odour, builds static, feels slick and can shine at a seam	Training, golf and running knits
Cotton-elastane	Stretch with recovery for fitted shapes, cuffs that spring back	Recovery depends on percentage and knit, and heat shortens its life	Leggings, fitted tees, rib collars and waistbands
Cotton-viscose	Drape at low weight, a cool hand, deep colour	Low strength when wet, so it needs a cool wash and flat drying	Drapey tees, resort shirts, soft dresses

What does 100% cotton give you, and what does it cost?

What you get is a hand synthetics do not reproduce, plus moisture behaviour that suits a garment worn against skin: cotton absorbs rather than wicks, so it feels dry in moderate heat and clammy once saturated. It takes dye, print and embroidery cleanly.

What you pay is movement. Cotton knits relax and shrink, and the neckline and cuff show it first. Pre-shrinking and a compacted finish reduce that without removing it, and neither survives a hot dryer. Put pre-shrink treatment on the fabric order and measure a washed sample; the 100% cotton polo specification carries that line, and the T-shirt manufacturing page covers the jersey weights.

When does cotton-polyester earn its place?

When the job is to look the same after many washes. The blend holds its measurements, dries faster than cotton and costs less per garment at the same weight, which is why uniforms and team kits sit here. It carries into fleece too, where a hoodie has to survive industrial laundering.

The cost is pilling at the points that rub, because two fibres of different strength abrade against each other, plus a surface that reads flatter than cotton. Approve the blend and the knit face on a washed sample rather than a swatch, and read the hoodie manufacturing page before moving a fleece programme.

What does 100% polyester do that cotton cannot?

It moves moisture instead of holding it. A polyester knit engineered for wicking carries sweat to the surface, where it evaporates, and the garment stays light because the fibre does not absorb water. It holds colour and shape, and knits at a low weight without the transparency of a thin cotton jersey.

The costs sit at skin level: polyester holds odour, builds static in dry air and feels slick rather than soft. A hydrophilic finish improves the hand, but odour behaviour belongs to the fibre. The golf polo fabric guide shows where this direction earns its cost.

How much elastane changes a cotton knit?

An elastane content of 1–2% is one fabric and 5% is another. At the low end a knit recovers after being pulled over the head and holds a rib edge; at 5% a garment stretches and returns across a fitted shape. Leggings we run sit at 220–280 gsm.

Both figures are conventions, not guarantees, and a percentage alone proves nothing, because recovery also comes from the knit structure and the finishing route. Specify the percentage and the recovery check you want, then approve both on a washed sample. Heat is the other half: elastane degrades in a hot wash and a hot dryer, so a garment that recovers on day one can bag at the knee by the tenth wash. The fleece and French terry comparison shows how much comes from the knit.

Why add viscose, and what does it cost?

Viscose buys drape. A cotton-viscose knit falls closer to the body than cotton at the same weight, feels cooler and takes deep colour, which is why it turns up in resort shirts rather than in workwear.

The cost is strength when wet. Viscose loses a large share of its tensile strength in water, so a wet garment can stretch out of shape and wear through at a fold. It needs a cool wash and flat drying, and it relaxes more than cotton in the first wash; the blend ratio decides how much of that reaches the garment.

How do you write a blend into the specification?

Five lines, in order. Composition by percentage for each component, written as a ratio such as 60/40 or 95/5, because a body in one blend and a rib in another are two specifications. A tolerance in percentage points for that composition, agreed in writing rather than assumed, plus the method that settles it. Yarn count, and whether the yarn is single or two-ply. Weight in gsm with the band you will accept. The dyeing and finishing route, because a compacted finish changes the hand.

Then the line that makes the rest checkable: which test settles a dispute. A composition statement without a tolerance and a method is an opinion. Sampling follows in 3–7 working days, and bulk in 15–25 days after sample approval and deposit.

Who decides whether the composition label is compliant?

The buyer does, for the market the garment is sold into. Labelling rules differ by country, so the composition statement, the fibre names allowed and the care-label language are your call, taken with that market’s rule in front of you.

What the factory owes is production to the composition you confirmed, and fabric that matches it. We do not certify a label for a destination market and we do not rule on whether a claim is compliant; we make to the confirmed line and pass on the mill documentation that came with the lot. The approved wording belongs in the tech pack, as the cutting and sewing page assumes it does.

Which blend assumptions turn out wrong?

Three, and they are common. Adding elastane does not make a garment keep its shape: recovery depends on how much is there and how the knit is built, and 1–2% against 5% is two fabrics with two lifetimes. A cotton-rich blend is not 100% cotton, and a fabric sold under a cotton name is still a blend, so the percentage has to be written down and checked, the same line the Pima and Supima comparison draws for cotton names.

The third is that poly-cotton is the cheap option. It is cheaper per metre at equal weight and pills most visibly, so the saving can reverse at the claims stage. A blend change also sends the order back through sampling, and bulk restarts at 15–25 days after sample approval and deposit. Approve the face on a washed sample.

What do buyers ask most about fibre blends?

Do cotton-polyester blends pill?

More than either fibre alone, at the points that rub: under the arm, at the cuff, where a bag strap sits. Pilling is abrasion plus loose fibre ends, and a blend mixes fibres of different strength, so the weaker ones work free. Approve the face on a washed sample, and write the pilling test and its acceptance level into the specification.

How much elastane does a knit need before it stretches?

Enough to recover the shape you are cutting, which depends on the pattern as much as the yarn: a rib collar and a fitted legging do not carry the same requirement. An elastane content of 1–2% is a usual starting point for a body that has to hold its line, and 5% belongs to garments cut close to the body.

Can a cotton-polyester blend be used for a hoodie?

Yes, and it suits programmes where the hoodie has to keep its shape through repeated laundering. The blend holds the body and the rib, dries faster, and pills at a brushed face. Hoodies we run sit at 240–550 gsm, and the blend goes into the specification with the weight you want.

Can a garment be labelled 100% cotton if it contains other fibres?

Not honestly, and in most markets not lawfully. The label states the composition of the garment or of each component, and a small share of another fibre is still a share. A tolerance covers variation in the test, not an undeclared blend. Confirm the wording for your market before the labels are ordered.

How is organic cotton different on a specification?

On the specification it is the same fibre line with a document behind it. The certificate belongs to the chain that holds it, from grower through gin and spinner, not to the factory that sews the garment. Ask for the transaction certificate naming the lot, and keep the label wording separate from the purchase order.

Does changing the blend require a new sample?

Yes. A different ratio changes the hand, the shrinkage behaviour and the way the garment takes decoration, so the approved sample no longer describes what will be produced. Treat a composition change as a new fabric: re-approve the cloth, re-cut the sample and record the new percentages. Sampling takes 3–7 working days once the fabric is in.

What should you send with the fibre line?

Send the composition by component with the tolerance you will accept, the yarn count and the knit, the weight band, the finish and the label wording for your market. The reply can then confirm what is sourceable and where the line needs narrowing. Minimum is 100 pcs per style, per colour; sampling takes 3–7 working days and bulk 15–25 days after sample approval and deposit, inspected 100% to AQL 2.5. Send the specification for a quote.