How to Read a Fabric Technical Sheet — And What It’s Actually Telling You

Most designers receive technical sheets from suppliers and focus on two numbers: the price and the MOQ. Everything in between gets a quick scan and a nod. This is understandable — technical sheets are not designed for readability. But the information they contain, if you know how to read it, tells you almost everything you need to know about whether a fabric is right for your project before a single sample is cut.

Here is what each specification actually means in practice.

GSM — Grams per Square Meter

This is the weight of the fabric. A higher GSM means a heavier, denser cloth. A lower GSM means lighter and more fluid. What it doesn’t tell you is how that weight is distributed — a loosely woven heavy fabric behaves completely differently from a tightly woven one of the same GSM. Weight is a starting point, not a conclusion.

For reference: a lightweight silk blouse fabric typically sits between 12–22 GSM. A structured wool suiting sits between 200–280 GSM. A cashmere coating can reach 400–600 GSM. If a supplier gives you a GSM that seems off for the category — ask why.

Momme — For Silk Specifically

Momme (mm) is the traditional weight measurement used for silk, and it works differently from GSM. It measures the weight of a defined length and width of fabric in pounds. The practical range for apparel silk is 8–30 momme. Below 12mm, the fabric will be very sheer and delicate. Above 22mm, you’re looking at a fabric with genuine body and durability. 30mm is considered luxury weight.

Many suppliers list momme without clarifying whether they mean the raw fabric or the finished, dyed cloth — which can differ. Always ask which stage the measurement refers to.

Fiber Content & Purity

A label that reads “100% Silk” is not the same as a specification that reads “Grade 6A Mulberry Silk, fiber purity ≥95%, naturally degummed.” The first is a declaration. The second is a specification you can hold someone to.

For cashmere, the critical figure is fiber diameter, measured in microns. Anything above 18 microns will feel noticeably coarser. Grade A cashmere sits between 14.5 and 15.5 microns. If a technical sheet lists cashmere fiber content without specifying micron diameter, that omission is itself informative.

Width

Standard fabric width in China is typically 110–150cm for wovens. Width matters because it directly affects your yield and therefore your real cost per meter. A fabric priced at $45/meter at 110cm wide costs you effectively more than one priced at $48/meter at 150cm wide, depending on your pattern pieces. Always calculate cost per square meter, not cost per linear meter, when comparing fabrics of different widths.

Shrinkage

A specification sheet should include pre-washing and post-washing dimensions. If it doesn’t, ask. Natural fibers shrink — silk less so, linen considerably more. If you’re working with linen or wool, a fabric without a stated shrinkage figure is a fabric whose behavior in production you don’t know.

Colorfastness Ratings

Colorfastness is rated on a scale of 1–5. A rating of 4–5 means the color is highly stable under washing, light, and perspiration. A rating of 3 means you will see fading. Anything below 3 is a problem waiting to happen. This specification is often omitted from supplier sheets — which means you need to ask for it directly, and for premium garments, request a lab test result.

The Number That’s Usually Missing

Thread count, pick count, or ends-and-picks per centimeter — the number of warp and weft threads per unit of fabric — is one of the most telling quality indicators for woven fabrics, and it’s frequently absent from supplier sheets. A higher thread count in the same fiber and weight indicates a more refined, denser weave. When comparing two fabrics of similar spec, ask for this figure. It explains a lot about why one drapes better than the other.