Question 1

What does GSM mean for knitted fabric?

Accepted Answer

GSM stands for grams per square metre and tells you how much one square metre of finished knitted fabric weighs. It is the most common way to compare fabrics: roughly 150 GSM is light, 180 GSM is medium and 300 GSM is heavy. GSM measures weight, not thickness or quality, and it depends on the yarn, the stitch density and the finishing.

When you compare offers, ask for the GSM of the finished fabric together with the tolerance. That is the only way to calculate consumption and cost per metre correctly.

Question 2

How do I convert GSM to oz/yd² and back?

Accepted Answer

To convert GSM to ounces per square yard, divide by 33.9; to go the other way, multiply by 33.9. For example, 180 GSM is about 5.3 oz/yd², and 8 oz/yd² is about 271 GSM. A quick mental shortcut is to multiply ounces by 34.

Buyers from the US and UK often quote weight in ounces, especially for hoodies and heavyweight tees. Always check whether the figure is oz per square yard (area) or ounces per linear yard, because they are different values and the gap can be large.

Question 3

What is ounces per linear yard and how do I convert it to GSM?

Accepted Answer

Ounces per linear yard (oz/ly) is the weight of one yard of fabric across its full width, so it depends on the width. The formula is oz/ly = oz/yd² × width in inches ÷ 36. For example, 8 oz/yd² at 60 inches wide gives 8 × 60 ÷ 36 = 13.3 oz/ly.

To get back to GSM, reverse the calculation and multiply by 33.9. Without the width, an oz/ly figure says nothing about the real GSM. When a foreign customer quotes a weight in ounces, ask which of the two units they mean.

Question 4

How do I measure GSM with a GSM cutter?

Accepted Answer

A GSM cutter punches out a disc of exactly 100 cm² (0.01 m²). Weigh the disc on a scale accurate to 0.01 g, then multiply the weight in grams by 100: a 1.80 g disc means 180 GSM.

In practice, lay the fabric relaxed and unstretched on a soft surface, cut at least three or four discs at different points across the width, and average them. Avoid the first 10 cm from the edge and any crease marks. Let the fabric rest in the room for about an hour so the moisture stabilises, otherwise the figure will be slightly off.

Question 5

How can I calculate GSM with just a ruler and a kitchen scale?

Accepted Answer

Cut a square of 20 × 20 cm (400 cm², or 0.04 m²), weigh it and multiply the weight in grams by 25. For example, 7.2 g × 25 = 180 GSM. A 10 × 10 cm square works the same way, but you multiply by 100 and need a 0.01 g scale, because a small error gets multiplied a lot.

Use a ruler or rigid template and a rotary cutter so the cut follows the wale line. An ordinary kitchen scale with 1 g steps is too coarse for small swatches. For reliable results use a larger sample or a laboratory scale.

Question 6

Where on the roll should I cut the sample for a GSM check?

Accepted Answer

Cut the sample from at least three points across the width (left, centre, right), at least 10 cm from the edge, and from a spot a few metres in from the end of the roll rather than the outer layer. The outer layer can be dry, marked or stretched differently.

For a large lot, check several rolls, not just one. Record the values separately and then average them. If the difference between points exceeds about 3–4%, the fabric has uneven weight and it is worth telling the supplier before you start cutting.

Question 7

Does GSM change between greige and finished fabric?

Accepted Answer

Yes, finished fabric is usually heavier per square metre than greige (raw) fabric. During dyeing and finishing the knit contracts in length and width, the stitches move closer together and the weight per square metre goes up, often by a few percent up to ten percent or more depending on the yarn and the process.

That is why an offer must state clearly that the GSM is the finished value. The GSM on the knitting machine is not the one you will cut. For consumption calculations always use the GSM and width of the delivered fabric, not the figures from the knitting sheet.

Question 8

How does GSM change after washing?

Accepted Answer

After washing, knitted fabric shrinks in length and width, so the same amount of material covers a smaller area and the GSM goes up. The formula is: new GSM = old GSM ÷ (length factor × width factor). For example, 180 GSM with 5% length shrinkage and 3% width shrinkage gives 180 ÷ (0.95 × 0.97) ≈ 195 GSM.

The total weight of the fabric does not change, only the area. If a specification requires a minimum GSM after washing, test a washed sample rather than an unwashed one and record how many washes were done.

Question 9

What GSM does a normal single jersey t-shirt have?

Accepted Answer

A classic single jersey t-shirt is usually between 140 and 200 GSM, most often 160 to 180 GSM. Below 140 GSM it is a very light summer or cheap promotional tee; 180 to 200 GSM is a solid tee with good opacity, often chosen for private-label brands.

For tees that will be printed or embroidered, 160 to 180 GSM is a good compromise between cost, opacity and comfort. White and light colours need slightly more weight so the skin does not show through. Ask for a swatch before deciding.

Question 10

What GSM should I choose for hoodies and sweatshirts?

Accepted Answer

French terry (2-thread) hoodies are typically 240 to 330 GSM, while 3-thread fleece with a brushed inside is typically 260 to 380 GSM. Above 350 GSM you are in heavy winter or streetwear territory.

A range of 280 to 320 GSM is a common starting point for brand hoodies because it gives body and drape without being too costly. For light sports sweatshirts or summer tops, 200 to 250 GSM is used. Do not compare french terry and fleece directly: at the same GSM the feel and warmth differ, so ask for samples.

Question 11

What GSM do pique polo shirts usually have?

Accepted Answer

Pique polo shirts typically weigh 180 to 240 GSM. A pique of 190 to 220 GSM is the classic choice for uniforms and branded polos because it holds its shape, does not crease easily and survives repeated washing.

Below 180 GSM the polo can feel thin and loses shape sooner; above 240 GSM it becomes a thick fabric better suited to cooler seasons. Collars and cuffs use rib fabric separately, with its own weight. If you produce uniforms worn daily, go toward the upper part of the range.

Question 12

What GSM is used for leggings, joggers and sportswear?

Accepted Answer

For leggings and sportswear the typical range is 180 to 280 GSM, with elastane. Opaque leggings that do not turn see-through when stretched usually start at 220 to 250 GSM. Joggers in french terry or fleece run 250 to 330 GSM, while running and training tees are 120 to 170 GSM.

For stretch fabrics, check the GSM after relaxation, because elastane makes the fabric contract. Opacity is tested by stretching the sample over your hand or a dark background. Too low a GSM in light-coloured leggings is a common cause of complaints.

Question 13

What counts as lightweight, midweight and heavyweight GSM?

Accepted Answer

There is no official boundary, but in practice for single jersey under 140 GSM is light, 140 to 200 GSM is medium and over 200 GSM is heavy. For french terry and fleece the scale moves up: light 180 to 240 GSM, medium 250 to 320 GSM, heavy over 330 GSM.

The category depends on the fabric type, so a single number can mislead: 250 GSM is a very heavy jersey but a midweight french terry. When you talk to a supplier, always state the knit type together with the GSM so you both mean the same thing.

Question 14

From what GSM is a t-shirt heavyweight (oversized, boxy)?

Accepted Answer

In the current heavyweight and oversized tee trend, a t-shirt counts as heavy from about 220 GSM; boxy streetwear tees usually use 240 to 280 GSM and some reach 300 GSM. A normal tee stays at 160 to 180 GSM.

The higher GSM gives a stiff drape and a square shape, but it raises the fabric consumption per tee by roughly 30 to 50% compared with a 180 GSM tee. So calculate cost per piece, not just per kilogram. Choose a thick-yarn jersey with low transparency and check shrinkage, since heavy tees can shorten noticeably after the first wash.

Question 15

From what GSM is a hoodie considered heavyweight?

Accepted Answer

A hoodie is considered heavyweight from about 350 GSM; between 400 and 500 GSM people speak of very heavy hoodies in the premium streetwear or American vintage style. Regular hoodies sit at 280 to 320 GSM.

The extra weight brings warmth, body and a premium look, but also higher fabric consumption and more difficult cutting. In 3-thread fleece the weight is felt more than in french terry. Check whether the quoted GSM was measured before or after relaxation, and ask for a sample so you choose the weight by drape and not only by the number.

Question 16

What is the difference between tubular and open-width knitted fabric?

Accepted Answer

Tubular fabric comes off the circular knitting machine as a tube and is delivered folded flat. Open-width fabric has been slit lengthwise and opened into a single flat piece. The open width is roughly double the flat width of the tube.

Tubular is more economical for cutting tees because you can avoid side seams, and it avoids slit-edge marks. Open width is preferred for complex marker layouts, for wide-format printing and for fabrics whose edges curl. Tell the supplier which type you need, especially if you work with different production methods.

Question 17

How do I read the width on a tubular roll label?

Accepted Answer

On a tubular roll label, the stated width is usually that of the tube laid flat, not the fabric opened out. A 90 cm tube is about 180 cm in open width. Some producers state the open width directly or the machine diameter in inches; ask them which value the number shows.

To check, put the roll on a table, flatten the tube without stretching it and measure from fold to fold. Double the result to get the open width. Without this clarification, mixing up 90 and 180 cm can ruin your whole metres-per-kilogram calculation.

Question 18

What is the usable width of a fabric?

Accepted Answer

Usable width is the part of the total width you can actually use when cutting. It is smaller than the nominal width because the edges can have pin marks, creases, waviness or shade differences. For open-width fabric the typical loss is 1 to 3 cm on each side; for tubular, it is around the fold line.

In marker planning always use the usable width, not the label width. If a supplier states 180 cm, the usable width may be 175 to 178 cm. A difference of just 3 cm can change marker efficiency and therefore consumption per piece, especially on large pattern pieces.

Question 19

What are the advantages of cutting from tubular fabric?

Accepted Answer

Cutting from tubular allows pieces without a side seam, for example a tee body made as one piece around the body. This reduces sewing time, removes the seam and gives a cleaner finish. At the same time, each tube diameter fits one garment size best.

The drawbacks: the tube width is fixed, so you cannot make different sizes from the same roll without high waste; the fold line mark must be avoided; and patterns or stripes across the width cannot be placed freely. For small runs and multiple sizes, open width offers more freedom.

Question 20

How do I measure the width of knitted fabric correctly?

Accepted Answer

Lay the fabric on a flat table with no stretching and no waves, and measure from edge to edge at right angles to the length. Take the measurement in at least three places along the roll, a few metres apart. Do not pull the fabric to get a bigger number, because knitted fabric stretches and then recovers.

For tubular, measure the width of the flat tube and double it. For fabrics with curling edges, measure the usable width without the folded zone. Note whether the measurement was taken relaxed or straight off the roll, because after a few hours of relaxation the width can change slightly.

Weight, width & measurement

What does GSM mean for knitted fabric?

How do I convert GSM to oz/yd² and back?

What is ounces per linear yard and how do I convert it to GSM?

How do I measure GSM with a GSM cutter?

How can I calculate GSM with just a ruler and a kitchen scale?

Where on the roll should I cut the sample for a GSM check?

Does GSM change between greige and finished fabric?

How does GSM change after washing?

What GSM does a normal single jersey t-shirt have?

What GSM should I choose for hoodies and sweatshirts?

What GSM do pique polo shirts usually have?

What GSM is used for leggings, joggers and sportswear?

What counts as lightweight, midweight and heavyweight GSM?

From what GSM is a t-shirt heavyweight (oversized, boxy)?

From what GSM is a hoodie considered heavyweight?

What is the difference between tubular and open-width knitted fabric?

How do I read the width on a tubular roll label?

What is the usable width of a fabric?

What are the advantages of cutting from tubular fabric?

How do I measure the width of knitted fabric correctly?

What is a normal GSM tolerance (±5%)?

What width tolerance is accepted for knitted fabric?

How do I convert kilograms of fabric into metres?

How do I calculate the kilograms needed from a number of metres?

How do I calculate metres per kilogram for tubular fabric?

How much does a linear metre of fabric weigh (grams per metre)?

How much does a roll of knitted fabric weigh and how many metres is it?

What is the difference between net and gross weight on fabric rolls?

Why do two rolls of the “same” fabric weigh differently?

How does moisture affect fabric weight?

How many t-shirts can I make from one kilogram of knitted fabric?

How many hoodies can I make from a 25 kg roll?

How much fabric does a tee, a polo, a hoodie and joggers use?

How much fabric should I order for 1,000 t-shirts?

What is a normal marker efficiency and how much is lost in cutting?

What shrinkage is normal for cotton knitted fabric?

How do I calculate the shrinkage percentage?

How is dimensional stability tested (ISO 6330, ISO 5077)?

How do I compensate for shrinkage in cutting patterns?

Should I let the fabric relax before cutting?

What is spirality (torque) in knitted fabric and how is it measured?

What spirality value is acceptable?

How do I test the stretch of a knitted fabric?

What are elastic recovery and growth in knitted fabric?

How does elastane change fabric width and GSM?

In which direction is stretch measured: lengthwise or crosswise?

How do I count wales and courses per centimetre?

Does a higher GSM mean a thicker fabric?

Does a higher GSM mean better quality?

What should I check when rolls arrive: weight, width and GSM?

If I buy by the kilogram, how do I make sure I have enough metres?

How can I find the length of a roll without unrolling it?

From stock, no minimum order.