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A polyester fabric specification sheet contains important information about the fabric's composition, weight, width, construction, yarn and performance. For garment manufacturers, clothing brands and wholesale fabric buyers, understanding these specifications makes it easier to compare fabrics and select the right material for production. A fabric may look similar to another fabric but have completely different specifications. Reading the specification sheet carefully can help avoid mistakes when ordering fabric in bulk. What Is a Fabric Specification Sheet? A fabric specification sheet is a document that provides important technical details about a fabric. Depending on the supplier and fabric type, it may include: Fibre composition Fabric name GSM DIA or width Yarn specification Fabric construction Colour Stretch Finishing Weight Performance information Not every supplier uses exactly the same format, so some specifications may be missing from a particular sheet. 1. Fibre Composition The first thing to check is the fibre composition. For example, a specification may state: 100% Polyester or a blended composition such as: Polyester + Elastane The composition tells you what fibres are present in the fabric. This is important because fibre composition affects characteristics such as: Comfort Stretch Durability Moisture behaviour Care requirements Printing suitability Always confirm the composition before placing a bulk order. 2. GSM GSM means Grams per Square Metre. It indicates the weight of the finished fabric per square metre. For example: 120 GSM 160 GSM 180 GSM 220 GSM Generally, a higher GSM means more fabric mass per square metre, but it does not automatically mean better quality. GSM should be considered together with: Yarn Construction Density Finishing Intended application 3. DIA For knitted fabrics, DIA generally refers to the fabric's diameter or usable width. It is an important specification for garment manufacturers because fabric width affects: Cutting Marker planning Fabric consumption Garment yield Production efficiency For example, a knitted fabric may be specified as: DIA 60 The exact usable width should be confirmed with the supplier because finished width can vary depending on the fabric and finishing process. 4. Yarn Specification The specification sheet may include information about the yarn used to manufacture the fabric. Depending on the fabric, you may see information related to: Spun yarn Filament yarn Textured yarn Yarn count Denier Yarn specification can influence: Surface appearance Hand feel Drape Strength Fabric texture Two polyester fabrics can therefore have different characteristics even when both are labelled simply as polyester. 5. Fabric Construction Fabric construction tells you how the fabric has been produced. For knitted polyester fabrics, examples may include: Single Jersey Piqué Interlock Rib Mesh Honeycomb Different constructions create different characteristics. For example, mesh can provide a more open structure, while interlock generally provides a more stable and compact construction. Construction should always be considered alongside GSM and yarn specification. 6. Fabric Width The specification sheet may list fabric width separately from DIA. Width is important because it affects how efficiently fabric can be used during garment cutting. When comparing suppliers, check whether the listed width is: Tubular width Open width Finished width Usable width This distinction can be important when calculating actual garment consumption. 7. Colour Colour information may include: Colour name Colour code Shade reference Pantone reference Lab-dip reference For bulk production, colour consistency is particularly important. A colour name such as "Navy" or "Royal Blue" may not be sufficient for production approval. For important orders, use an approved physical sample or shade standard. 8. Finishing A specification sheet may mention the type of finishing applied to the fabric. Finishing can affect: Softness Smoothness Hand feel Drape Surface appearance Dimensional stability For example, two polyester fabrics with similar GSM and construction can feel different because of different finishing treatments. 9. Stretch If the fabric contains elastane or has a stretch construction, the specification may provide stretch information. This can be particularly important for: Activewear Leggings Track pants Sportswear Fitted garments You may need to check both: Stretch — how much the fabric extends. Recovery — how well the fabric returns toward its original dimensions. A fabric with good stretch but poor recovery may not be suitable for garments that need to maintain their shape. 10. Weight Some specification sheets may provide fabric weight in addition to GSM. Be careful to understand exactly what the listed weight represents. For fabric purchasing, GSM is generally more useful for comparing the weight of the finished fabric per square metre. If a supplier gives a weight specification that is unclear, ask them to clarify the measurement basis. 11. Performance Properties Some specification sheets may include additional performance information. Depending on the intended fabric, this could include: Breathability Moisture management Quick drying Stretch Recovery Colour fastness Abrasion resistance Pilling performance Dimensional stability Not every fabric specification sheet will contain all of these properties. Where a particular performance characteristic is important, ask for the relevant test information rather than assuming it from the fabric name. 12. Fabric Finish and Hand Feel Technical specifications don't always fully describe how a fabric feels. A specification may tell you: 100% Polyester / 180 GSM / DIA 60 but this does not completely tell you whether the fabric feels: Soft Smooth Dry Crisp Fluid Structured Textured For this reason, a physical fabric sample is extremely useful when evaluating a material. 13. Understanding a Sample Specification Imagine a polyester fabric specification looks like this: Specification Example Fibre 100% Polyester Construction Single Jersey GSM 180 DIA 60 Yarn Polyester Colour Navy Finish Soft Finish Application T-Shirts This tells you several important things. 100% Polyester The fabric is made from polyester. Single Jersey It uses a knitted construction commonly used for apparel. 180 GSM The finished fabric weighs approximately 180 grams per square metre. DIA 60 The knitted fabric has a specified diameter/width that should be confirmed with the supplier. Soft Finish The fabric has undergone finishing intended to influence its hand feel. T-Shirts The supplier indicates an intended application, but the final suitability should still be evaluated based on your garment requirements. 14. Don't Judge Fabric Only by GSM One common mistake among new fabric buyers is assuming: Higher GSM = Better Fabric This is not always true. For example: A 160 GSM sportswear fabric may be more suitable for a lightweight jersey than a 220 GSM fabric. Similarly, a 220 GSM fabric may be preferable for another garment where greater body or coverage is required. The correct GSM depends on: Garment type Climate Construction Comfort requirements Performance requirements Target price 15. Don't Judge Fabric Only by DIA DIA is important for production, but it does not tell you everything about fabric quality. Two fabrics can have the same DIA but different: GSM Yarn Construction Hand feel Stretch Drape Performance Always read the complete specification. 16. Check the Fabric Sample Alongside the Specification The best approach is to use the specification sheet together with a physical fabric sample. Check: Visual Appearance Does the surface look consistent? Hand Feel Does it feel as expected? Drape Does it fall correctly? Stretch Does it have the required flexibility? Recovery Does it return to shape? Colour Does it match the approved shade? Surface Are there visible defects? Washing Does the fabric maintain its appearance after washing? 17. Questions to Ask Your Fabric Supplier If something is unclear on the specification sheet, ask the supplier: What is the exact fibre composition? What is the actual GSM? What is the usable DIA or width? What yarn is used? What is the fabric construction? What finishing has been applied? Does the fabric have stretch? What is the recovery performance? What are the colour-fastness results? Is the specification consistent throughout the bulk roll? Can you provide a physical sample? Can you provide relevant test reports? These questions can help reduce misunderstandings during bulk purchasing. 18. Why Specification Sheets Matter for Bulk Orders A fabric specification sheet becomes especially important when ordering large quantities. It helps buyers compare: Supplier A vs Supplier B based on measurable specifications rather than appearance alone. It can also provide a reference for checking whether the delivered fabric matches the agreed requirements. For repeat orders, maintaining the approved specification and sample can help improve consistency between batches. Quick Fabric Specification Checklist Before approving a polyester fabric, check: ✅ Fibre composition ✅ GSM ✅ DIA / usable width ✅ Yarn specification ✅ Fabric construction ✅ Colour ✅ Finishing ✅ Stretch ✅ Recovery ✅ Hand feel ✅ Drape ✅ Breathability ✅ Durability ✅ Washing performance ✅ Relevant test reports Frequently Asked Questions What is a polyester fabric specification sheet? It is a document containing technical information about a polyester fabric, such as composition, GSM, DIA, yarn, construction, colour and finishing. What is the most important specification? There is no single most important specification. GSM, DIA, yarn, construction and performance should be considered together based on the intended garment. Is GSM the same as fabric thickness? No. GSM measures fabric weight per square metre. Thickness and hand feel can vary depending on yarn and construction. What does DIA mean in knitted fabric? DIA generally refers to the diameter or width specification of knitted fabric. The exact usable width should be confirmed with the supplier. Why is yarn specification important? Yarn characteristics can influence the fabric's surface, hand feel, drape, strength and overall performance. Should I buy fabric based only on the specification sheet? No. Use the specification sheet together with a physical sample and, where necessary, appropriate test reports. Final Thoughts Learning to read a polyester fabric specification sheet makes fabric purchasing much easier. The most important specifications to understand are: Fibre Composition + Yarn + GSM + DIA + Construction + Colour + Finishing + Performance But specifications are only part of the decision. For garment manufacturers and wholesale buyers, the best approach is to compare the technical specification with the physical fabric sample and confirm the material meets the requirements of the final garment before placing a bulk order.