How to read fabric specs before you buy

Fiber content

Prefer exact percentages over category words. “100% linen” and “60% cotton / 40% linen” tell you how the cloth will press, breathe and pill. “Poly blend” does not. Percentages also tell you what a blend is doing: a few per cent of elastane is stretch, a third of polyester is wrinkle resistance bought at the cost of breathability.

What each fiber gives you

• Cotton — takes a crisp press, washes hard, dyes brilliantly. The everyday natural fiber, and the most forgiving to sew.
• Linen — cool, strong, and wrinkles as part of the deal. Softens with every wash. Frays fast at cut edges, so finish seams early.
• Hemp and bast blends — the durable end of natural fiber. Stiff off the bolt, excellent after a few launderings.
• Rayon and viscose — plant-derived but chemically processed. Wonderful drape, weak when wet, and prone to real shrinkage.
• Polyester and nylon — cheap, stable and non-absorbent. Fine for bag linings and structure; less pleasant against skin in heat.
• Elastane / spandex / Lycra — 2–5% is enough to change how a woven behaves and which needle you need.

GSM, ounces and weight

GSM (grams per square metre) is how heavy the cloth feels by area. It is the single most useful number on a listing, because it is independent of bolt width — a 130 gsm cotton is a 130 gsm cotton whether it is cut at 44 or 60 inches. Some mills publish ounces per square yard instead; multiply by roughly 33.9 to convert to GSM.

If a shop only says “medium weight,” ask for a number or order a swatch. Here is roughly where things sit:

Bands overlap because finishing changes everything — a resin-finished 120 gsm poplin feels stiffer than a washed 160 gsm linen. Treat GSM as the first filter, then read the hand description.

Width and usable width

Width decides how many yards you actually need. Quilting cotton is generally 42–45 inches on the bolt, with about 42 inches usable once you trim the selvages. Apparel cloth is often 54–60 inches. Pattern envelopes publish separate yardage columns for each width for exactly this reason, and the gap is not small — a dress that takes 2 yards at 60 inches can want 3 or more at 45.

Check the listing width before you add to cart, and check whether a stated width includes the selvage. When a kit includes fabric, we state the width we cut from. More on matching widths to a pattern in beginner sewing patterns.

Hand, drape and opacity

Hand is how it feels — soft, crisp, cool, dry, scratchy, papery. Drape is how it falls — fluid for gathers and bias, structured for tailored shapes. Opacity decides whether you are also buying lining. Photographs rarely show all three; good copy does.

When a swatch arrives, three tests take under a minute. Drape it over the back of your hand and see whether it breaks into soft folds or stands away in cones. Hold it up to a window with your hand behind it for opacity. Scrunch it in a fist for ten seconds and release to see how hard it wrinkles and whether the creases fall out.

Stretch and recovery

Wovens with elastane usually stretch in one direction (across the width) and are called two-way; knits often stretch both ways. Patterns written for knits state a required percentage — fold 4 inches of cloth against a ruler and pull: if it reaches 6 inches comfortably, that is 50% stretch.

Recovery matters as much as stretch. Cloth that goes to 50% and does not spring back gives you baggy knees and cuffs. Stretchy fabric also changes your needle: use a ballpoint or stretch point rather than a universal, which is covered in tools for sewing beginners, or browse needles by point type.

Shrinkage, prewash and care

Natural fibers shrink, mostly on the first wash. Prewash yardage the way you intend to wash the finished garment — same temperature, same dryer setting — then press and cut. Skipping this is the most common reason a well-sewn first garment stops fitting.

Cotton — expect 3–5%

Most of it lands in the first hot wash. Quilting cotton usually sits at the lower end.

Linen and linen blends — expect 5–10%

Wash and dry twice before cutting if the finished garment will go through a dryer.

Hemp and bast blends — expect 4–8%

Softens noticeably with each wash — the hand you buy is not the hand you keep.

Rayon and viscose — expect up to 10%

Loses body when wet. Hand wash or use a mesh bag, and never guess at yardage.

Buy roughly 10% more than the pattern asks for when you are working with linen or rayon, or when the listing does not state shrinkage at all. Care instructions should match the fiber rather than repeat a generic icon set: an unlined linen dress and a quilt made from the same weight of cotton do not want the same laundry.

Grain, selvage and bias

The selvage is the finished edge that runs the length of the bolt. Parallel to it is the lengthwise grain, which is the most stable direction and where most pattern pieces are placed. Across the bolt is the crosswise grain, which gives a little. At 45 degrees is the bias, which stretches and drapes and is why bias-cut skirts hang the way they do.

Cutting off-grain is what makes a finished side seam twist around the leg. Before you cut, square the cloth up: snip the selvage and tear or pull a thread across the width to find true crosswise grain, then press. Directional prints and one-way naps need every piece laid the same way, which quietly increases the yardage you need.

Garment cotton vs quilting cotton

Quilting cotton is stable and crisp — excellent for patchwork and some structured garments, less ideal when a pattern wants fluid drape. Apparel-oriented lawn, voile, gauze and linen behave differently: they are lighter, they move, and they punish an imprecise seam allowance. Match the cloth to the pattern’s recommended fabrics, not just the print.

A useful rule: if the pattern illustration shows the fabric hanging in soft vertical folds, you need drape. If it shows the garment holding a shape away from the body, you need body. Our natural fiber clothing guide works through this fiber by fiber, and sewing dresses with natural fibers does it silhouette by silhouette.

The spec block we look for

Every fabric listing — ours or anyone else’s — should be able to answer these eight things. Where we do not know a figure, we leave it blank and say so rather than invent it.

• Fiber content as exact percentages, not a category word
• Width in inches, and whether that figure includes the selvage
• Weight in GSM or ounces per square yard — or an honest blank
• Hand and drape in plain language: soft or crisp, fluid or structured
• Opacity: sheer, semi-opaque or opaque
• Stretch percentage and direction, if there is any
• Care instructions that match the fiber, not a generic icon set
• How the cut is measured, and whether multiple yards ship continuous

Mill, country of origin and organic or OEKO-TEX claims appear only when a supplier substantiates them. The full version of that commitment lives on our Quality & Sourcing Promise.

Questions people ask

What does GSM mean in fabric?

GSM is grams per square metre — how heavy the cloth is by area, independent of how wide the bolt is. Quilting cotton is roughly 110–150 gsm, mid-weight linen 150–200 gsm, and canvas 280 gsm and up. To convert from the ounces figure some mills publish, multiply ounces per square yard by about 33.9.

What weight of fabric should I use for a dress?

Most dresses land between 110 and 200 gsm. Go lighter (voile, lawn, gauze) when the pattern wants gathers, ruffles or bias fall; go heavier (mid-weight linen, poplin, chambray) when it wants collars, button bands and A-line structure to hold their shape.

How much fabric shrinkage should I expect?

Plan for 3–5% on cotton, 5–10% on linen, and up to 10% on rayon. On a 3-yard cut that is a loss of up to 10 inches, so prewash the yardage exactly the way you intend to launder the finished piece, then press and cut. If a listing does not state expected shrinkage, test a swatch before you commit.

What does 45 or 60 mean on a fabric listing?

Those are bolt widths in inches. Quilting cotton is usually sold at 42–45 inches with roughly 42 inches usable once you trim the selvage; apparel cloth is often 54–60 inches. Pattern yardage charts are written per width, so buying 45-inch cloth against a 60-inch chart will leave you short.

How can I tell if fabric will be see-through?

Opacity tracks weight and weave more than color, and pale solids show the most. A listing should say sheer, semi-opaque or opaque outright. If it does not, assume anything under about 110 gsm will need lining or a slip, and order a swatch to hold against your hand.

Is quilting cotton good for clothing?

Yes for crisp shapes — shirts, gathered skirts, pinafores, pyjamas and accessories. It is a stable, tightly woven cloth that presses beautifully and forgives a wobbly seam, which is why it is the best fabric to learn on. It will not drape like lawn, rayon or lightweight linen, so check the pattern's recommended fabrics before you cut.