How Cotton Is Made Into Fabric: Boll to Finished Cloth

Pick up a cotton T-shirt and it feels simple. Soft, light and plain. But how cotton is made into fabric is a long story, because that shirt began as a fluffy white boll on a plant and went through at least ten different steps before it reached your wardrobe. Many of those steps happen in different countries. Some take only minutes. Others take days.

This guide explains each stage in plain language. You will see what happens in the field, the gin, the spinning mill, the weaving or knitting mill and the dyeing house. There is also a worked example that follows a single 170 kg bale of cotton all the way to metres of fabric and finished T-shirts. If you only want the quick version, jump to the summary table near the end.

The big picture

Here is the whole route in one line.

Cotton boll → seed cotton → lint → yarn → fabric → dyed and finished fabric → garment

Each arrow is a separate process, often run by a separate company, sometimes in a separate country, and every handover adds cost, waiting time and a little waste. A farmer grows the cotton. A ginner separates the fibre from the seed. A spinner turns fibre into yarn. A weaver or knitter turns yarn into fabric. A dyer colours and finishes it. A garment factory cuts and sews it.

Bangladesh sits in the middle of this chain. Its spinning mills, knitting mills, dyeing houses and garment factories are large, but most of the raw cotton is bought from other countries. That is why a basic knowledge of cotton fibre is useful for anyone in the industry, from merchandisers to quality teams.

Stage 1: Growing and picking

Cotton is grown in warm regions with a long frost-free season. The plant flowers, the flower falls, and a green boll forms. When the boll ripens it splits open and the white fibre pops out, attached to the seeds. This mix is called seed cotton.

Picking is done in two ways:

• By hand. Workers pick open bolls by hand, which gives cleaner cotton with less trash (leaf and stalk pieces). It is common in many countries.
• By machine. Pickers or strippers harvest large fields fast, but more leaf and trash come along with the cotton.

The seed cotton is pressed into big modules or bundles and sent to a gin.

Stage 2: Ginning

At the gin, machines pull the fibre away from the seed. A saw gin uses rotating saw teeth to catch the fibre while the seeds fall away. A roller gin uses a leather or composite roller and is gentler, so it is often used for long staple cotton. Our guide to the ginning process of cotton goes through both types.

What comes out of the gin is called lint. The seeds are not wasted. They go to oil mills for cottonseed oil, and the leftover meal is used as animal feed.

The proportion of lint in the seed cotton is called ginning outturn or lint turnout. For many cottons it falls in the range of about 33 to 40 percent. A 35 percent outturn means that 100 kg of seed cotton gives about 35 kg of lint.

The lint is then pressed into bales. Bale weights differ by country. A bale of about 170 kg is common in several markets, and a bale of about 218 kg (480 pounds) is the standard in the United States.

Stage 3: Grading and testing

Before a spinning mill buys cotton, it checks the quality. The main properties are:

Property	What it tells you
Staple length	How long the fibres are. Longer fibres make stronger, smoother yarn.
Micronaire	Fineness and maturity of the fibre.
Strength	How much force the fibres can take before they break.
Uniformity	How even the lengths are.
Colour and trash	How white the lint is and how much leaf is left in it.

These tests are often done on an instrument line in a lab. The mill then mixes bales from different lots to get steady quality, which is called bale laydown or bale management. It helps to keep yarn from changing shade or strength from one batch to the next. To learn how fibre quality shows up in clothing, see our guide to cotton fabric for T-shirts.

Stage 4: Spinning cotton into yarn

Fibres alone cannot be woven or knitted. They must be cleaned, straightened and twisted together into a continuous strand. That strand is yarn. Our overview of the yarn making process from fibre to yarn covers it in depth, so here is the short version.

1. Blowroom. Machines open the compressed tufts of cotton, remove dirt and trash, and mix the lots.
2. Carding. Wire-covered rollers separate the fibres one by one and pull them roughly parallel. The output is a loose rope called a sliver. This is where short fibres and tiny neps (small knots) are cut down.
3. Combing (for finer yarn). A comber removes the shortest fibres and aligns the rest even more. This step costs more and removes extra waste, but gives a smoother, stronger, finer yarn. See the difference between the carded yarn and combed yarn routes.
4. Drawing. Several slivers are joined and stretched so they become even and the fibres line up.
5. Roving. The sliver is thinned and given a little twist to form a roving, which is wound onto a bobbin.
6. Ring spinning. The roving is drafted again, twisted and wound onto a bobbin. Twist gives the yarn its strength.

Other systems exist, such as open-end (rotor) spinning and air-jet spinning. They are faster and cheaper, with some difference in feel and strength.

Yarn count

Spinners describe how fine the yarn is with a count. In the English system (Ne), a higher number means a finer yarn. For example, 30s Ne is finer than 20s Ne. In the tex system, a lower number means finer yarn. You can convert with tex = 590.5 ÷ Ne. A 30s Ne yarn is about 19.7 tex, and a 40s Ne yarn is about 14.8 tex. For the basics, see our page on yarn count.

Stage 5: Turning yarn into fabric

There are two main ways to make cotton fabric. Each gives a different feel and look. Our comparison of woven and knit fabric lays out the details.

Weaving

Weaving crosses two sets of yarn at right angles. The lengthwise yarns are the warp and the crosswise yarns are the weft.

1. Warping and sizing. Hundreds or thousands of warp yarns are wound side by side onto a beam. Many are coated with a starch-like size to protect them from rubbing on the loom. See how warping machines work.
2. Weaving. On the loom, the warp yarns are lifted in patterns. The weft yarn passes through the opening and is beaten into place. Plain weave, twill and satin are three basic patterns.
3. Inspection. The fabric, called greige or grey cloth, is checked for faults.

Woven cotton is used for shirts, trousers, denim, bed linen and towels. Our step-by-step guide to the weaving process from yarn to fabric walks through each part.

Knitting

Knitting makes fabric by looping yarn through itself. Instead of two sets of yarn crossing each other, one yarn (or many) forms a chain of loops. This gives natural stretch and softness. T-shirts, polo shirts, underwear and hoodies are mostly knitted. For machine parts, see our guide to the parts of a knitting machine.

Stage 6: Preparation, dyeing and finishing

Grey fabric is not ready to wear. It has natural waxes, size, oil and a creamy colour. The wet processing mill cleans and colours it.

Step	What it does
Singeing (woven)	Burns off surface hairs so the fabric looks smooth.
Desizing (woven)	Removes the size that was added to the warp.
Scouring	Washes out natural waxes and dirt so the fabric can absorb water and dye.
Bleaching	Whitens the cloth, usually with hydrogen peroxide.
Dyeing	Adds colour. Reactive dyes are the usual choice for cotton.
Printing (optional)	Adds patterns.
Finishing	Gives a final hand feel, width and stability, for example by softening, stentering or compacting.

For the dye step, read our guide to the cotton dyeing process with reactive dyes. For the heat setting and width control stage, see stenter machines for textile finishing.

Two other treatments are common. Mercerising treats cotton with a strong caustic soda solution under tension. It makes the fibre swell, which adds lustre, strength and better dye uptake. Pre-shrinking (for example, compacting a knit or sanforising a woven) reduces the chance that a garment shrinks in the first wash.

A worked example: one bale to T-shirts

Let us follow one bale through the chain with simple, rounded numbers. These are example assumptions, since real losses depend on the mill, the cotton and the yarn type.

Starting point

• One bale of lint: 170 kg
• Target yarn: 30s Ne carded ring-spun, for single jersey T-shirt fabric
• Spinning loss (blowroom, card and other waste): 12 percent
• Knitting loss: 2 percent
• Dyeing and finishing weight loss: 6 percent
• Fabric: single jersey, 160 GSM, open width 1.8 m
• T-shirt: 0.2 kg of finished fabric each, including cutting waste

Step 1: Seed cotton behind the bale

With a 35 percent ginning outturn, seed cotton needed = 170 ÷ 0.35 = about 486 kg. The other 316 kg or so is mostly seed, along with some trash.

Step 2: Yarn

Yarn = 170 × (1 − 0.12) = 149.6 kg

Step 3: Length of yarn

For 30s Ne, tex = 590.5 ÷ 30 = 19.68. That means 1,000 m of yarn weighs 19.68 g. So 1 kg holds 1,000 ÷ 19.68 = about 50.8 km of yarn. Then 149.6 kg holds roughly 149.6 × 50.8 = 7,600 km of yarn. Laid end to end, that is a long road. All from one bale.

Step 4: Grey knit fabric

Grey fabric = 149.6 × (1 − 0.02) = 146.6 kg

Step 5: After dyeing and finishing

Finished fabric = 146.6 × (1 − 0.06) = 137.8 kg

Step 6: Metres of fabric

Length of fabric = weight in grams ÷ (GSM × width in metres)

= 137,800 ÷ (160 × 1.8) = 137,800 ÷ 288 = about 478 m

If you need a refresher on GSM, see our page on GSM meaning and calculation.

Step 7: T-shirts

T-shirts = 137.8 ÷ 0.2 = about 689 pieces

So a single 170 kg bale becomes roughly 690 T-shirts under these assumptions. Each shirt uses about 0.2 kg × 50.8 km per kg, or roughly 10 km of yarn. That number surprises most people.

Summary of the losses

Stage	Weight left (kg)
Lint in the bale	170.0
Yarn	149.6
Grey fabric	146.6
Finished fabric	137.8

About 19 percent of the lint weight is lost along the way. (170 − 137.8 = 32.2 kg, and 32.2 ÷ 170 = 18.9 percent.) Most of it is spinning waste, which is often sold to other mills for lower-grade yarn, along with impurities washed out in scouring and bleaching.

Time and water

The whole route takes weeks to months. A cotton crop needs several months to grow. Ginning takes hours. Spinning a lot of yarn takes days. Weaving or knitting takes days. Dyeing and finishing takes about a day or two for a lot. Cutting and sewing adds more days.

Cotton is a thirsty crop and wet processing also uses a lot of water, so many mills now focus on recycling water, better dye methods and lower chemical use. Sustainable and organic cotton schemes try to reduce the impact in the field as well. If you are sourcing, ask for details instead of trusting a label alone.

Quick summary table

Stage	Input	Output	Who does it
Growing and picking	Cotton plant	Seed cotton	Farmer
Ginning	Seed cotton	Lint and seed	Ginner
Spinning	Lint	Yarn	Spinning mill
Weaving or knitting	Yarn	Grey fabric	Weaving or knitting mill
Wet processing	Grey fabric	Dyed, finished fabric	Dyeing and finishing mill
Garment making	Finished fabric	Clothes	Garment factory

Final thoughts

Cotton fabric looks simple, but it is the product of many careful steps. The farmer picks the boll, the gin separates the fibre, the spinner makes yarn, the weaver or knitter forms the cloth, and the dyer gives it colour and hand feel. Along the way, a fair share of the weight is lost and a lot of skill goes in.

Our worked example showed that one 170 kg bale can become around 690 T-shirts, using roughly 7,600 km of yarn. Numbers like these help a buyer, a merchandiser or a student see where cost and waste come from. If you want to go deeper into one stage, pick the spinning route or the dyeing route first, since those shape the quality of the final fabric the most.

Frequently asked questions