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Woolen Fabric GSM vs Grams per Metre

Comparing a cloth quoted in GSM with one quoted in grams per linear metre? Normalize the units and width before deciding which sample is heavier.

Fred Textile flannel photographic fabric reference
Representative fabric direction. Specifications and sample availability are confirmed by Fred.

GSM and linear-metre weight calculator

Use the declared weight and the same width basis. The result converts units; it does not verify a product specification.

Example only: 400 GSM × 1.50 m = 600 g/m; 600 g/m ÷ 1.50 m = 400 GSM.

What the two numbers describe

GSM is mass per square metre. Grams per linear metre is the mass of one metre of cloth across its stated width. They describe different areas, so the numbers are not interchangeable. A wider fabric can have a larger linear-metre weight while its GSM stays the same.

For a width expressed in metres, GSM equals grams per linear metre divided by width. For example, a declared 600 g/m across a 1.50 m width corresponds mathematically to 400 g/m². This is a unit-conversion example, not a specification for any reference in this library.

Make the width basis explicit

Ask whether the width used in the weight declaration is total width or usable width. Do not replace one with the other silently. Keep the original supplier value, unit and width basis together in your comparison notes, then ask for the finished article specification.

A sample measurement, a nominal specification and an agreed production tolerance are different records. Note which one you have. When physical measurement matters, agree the conditioning and test method with the supplier or laboratory rather than treating a small unconditioned cutting as the final bulk result.

Use the converted figure as one comparison input

Equal GSM does not prove equal drape, thickness, stiffness or warmth. Fibre composition, yarn, construction and finishing can change how two references behave in the same garment. Compare the proposed samples with the same garment intent and construction plan.

Put the converted number in your worksheet as a comparison value and keep the underlying source visible. If width or units are missing, leave the calculation open and request clarification. A precise-looking result calculated from an unknown width creates a misleading comparison.

A practical record for your sample discussion

DecisionRecordQuestion for Fred
Declared weightValue and exact unitGSM or g/m?
Width basisMetres, total or usableWhich width was used?
Physical resultMethod and conditionMeasured or nominal?
Garment decisionDrape and construction trialWhat else needs comparison?

Questions buyers ask

Is 600 g/m heavier than 400 GSM?

It depends on the width basis. At 1.50 m, 600 g/m converts to 400 GSM. Compare the same units and confirmed width.

Does higher GSM mean a warmer coat?

GSM describes mass per area. It cannot provide a temperature rating or guarantee the warmth of the complete garment.

Can I filter this library by GSM?

The reference photographs currently have no documented article-level GSM. Ask Fred to propose articles within your target range.

Related wool fabric questions

From direction to development

Turn this question into a sample brief

Keep the reference, target and open questions together before contacting Fred.