GSM vs GLM in Textiles: What Is the Difference?

GSM stands for Grams per Square Metre. It is the weight of one square metre of fabric, measured in grams. If you cut a perfect 1 m × 1 m square from a fabric and weigh it on a scale, the reading in grams is the GSM.

GSM is the most widely used fabric weight measurement in textile trading globally. Its primary advantage is that it is independent of fabric width — a 180 GSM fabric is 180 GSM whether it is woven at 36 inches or 58 inches. This makes it ideal for comparing fabrics across different constructions and widths, and for communicating fabric weight in technical specifications.

As a rough reference for common fabric categories: lightweight shirtings typically fall between 80–120 GSM. Medium-weight shirtings sit at 130–180 GSM. Bottom-weight fabrics and chinos range from 200–280 GSM. Suiting fabrics are generally 220–350 GSM. Denim starts around 280 GSM and runs past 450 GSM for heavy weights. These ranges are indicative — exact GSM depends on yarn count, construction, and finish.

GSM is measured using a GSM cutter (a circular cutter of known area) and a precision scale. Laboratories take multiple samples from different parts of the fabric and average the readings to account for variation across the roll.

GLM stands for Grams per Linear Metre. It is the weight of one running metre of fabric at its actual loom width — sometimes called "grams per running metre" or simply "weight per metre." If you cut a 1-metre length of fabric at full width and weigh it, the reading in grams is the GLM.

Unlike GSM, GLM is width-dependent. The same fabric will have a different GLM depending on the width it is woven at. A 180 GSM fabric at 150 cm width will have a higher GLM than the same 180 GSM fabric woven at 90 cm width, because each running metre contains more fabric.

GLM is the more useful measurement when you are working with a fixed loom width and need to calculate fabric cost or quantity. Purchase orders are placed in metres (linear), not in square metres. If you know the price per kilogram and the GLM, you can calculate the price per running metre directly. If you know how many metres you need to cut, you know the exact weight of fabric you will consume.

For these reasons, GLM appears frequently in costing sheets, purchase orders, and quantity estimation for production planning — wherever the actual physical metre of fabric, not an abstract square metre, is the unit that matters.

GLM is derived from GSM and width using a straightforward formula:

Example 1. A fabric with GSM 180, woven at 150 cm width (approximately 58 inches):

Example 2. The same 180 GSM fabric, woven at 90 cm width (approximately 36 inches):

The same fabric, same construction, same GSM — but very different GLM depending on width. This is why GLM must always be quoted alongside the width it was calculated at. A GLM figure without a width reference is not meaningful on its own.

Use GSM when: you are comparing fabric weights across different constructions or widths; communicating a fabric's weight in a technical specification or sample record; describing a fabric in a catalogue, specification sheet, or sample sticker where width may vary; or testing and certifying fabric weight in a laboratory.

GSM is the universal language of fabric weight. When a buyer asks "what is the weight of this fabric?" they almost always expect a GSM figure. When a lab certifies fabric weight, the report is in GSM. When a specification sheet describes a construction, GSM is the standard field.

Use GLM when: you are calculating fabric cost per metre at a specific loom width; writing a purchase order where the width is fixed and you need to know weight per physical metre; estimating how much fabric a production run will consume; or comparing the cost of fabric at different widths where the production width is already determined.

GLM is the operational unit. Once the loom width is fixed and fabric is moving through production, the linear metre is what gets consumed. Costing done in GSM — without converting to GLM at the actual width — will produce incorrect results.

In practice, most textile operations quote both. A sample record will carry the GSM (the intrinsic fabric property) and the GLM (the weight at the specific width this design is being made at). Having both on record eliminates the need to recalculate each time.

SampleLedger stickers display both GSM and GLM because buyers and production teams use both in different contexts — often in the same conversation. A buyer examining a physical sample at a showroom wants to know the GSM to understand how heavy the fabric feels and how it compares to other constructions they are considering. The same buyer, when calculating the cost of producing 5,000 metres, needs the GLM to run the numbers.

Having both on the physical sticker means neither party needs to stop and calculate. GSM tells you what the fabric is; GLM tells you what it costs per metre at that width. You can learn more about the sticker fields and how SampleLedger handles fabric specifications on the fabric sample tracking features page.

The following table provides typical GSM ranges for common woven fabric categories. These are indicative ranges — actual GSM for any specific design will depend on yarn count, construction density, and finishing treatment.