Cotton fabric is made from the natural fibers of the cotton plant, a member of the Gossypium genus. Each fiber is a single cell that grows from the surface of a cottonseed, and a mature cotton fiber is over 90% cellulose, the same structural carbohydrate that gives wood and paper their rigidity. The remaining fraction includes natural waxes, pectin, and small amounts of protein and minerals.
From Seed to Fiber
A cotton fiber starts as a tiny tubular outgrowth on the surface of a cottonseed. Over the course of roughly 50 days, this single cell elongates and builds up layers of cellulose until it reaches its full length. When the cotton boll (the protective capsule surrounding the seeds) splits open, the fibers dry out and become the fluffy white material you’d recognize in a field.
Each fiber has a layered structure, almost like a microscopic cable. The outermost layer is a thin cuticle made of fats, waxes, and resins, less than 0.25 micrometers thick. Beneath that sits the primary wall, a mesh of pectin and cellulose strands woven in crisscrossing spirals. The bulk of the fiber is the secondary wall, where dense, crystalline cellulose is deposited in thick layers. At the very center is a hollow channel called the lumen, which carried nutrients to the living cell during growth. Once the fiber dries, the lumen collapses, giving cotton its characteristic flat, twisted ribbon shape under a microscope. That natural twist is what allows cotton fibers to lock together when spun into yarn.
Why Cellulose Matters for Comfort
Cellulose molecules have a chemical structure that attracts and holds water. This is why cotton can absorb roughly 25 to 27 times its own weight in water, making it one of the most absorbent common fabrics. When you sweat, cotton pulls moisture away from your skin and holds it within the fiber walls, which is why a cotton t-shirt feels cool against your body on a warm day.
That same cellulose structure also makes cotton breathable. Air moves relatively freely through the spaces between cotton yarns, and as trapped moisture evaporates, it carries heat away from the body. The tradeoff is that cotton stays wet for a long time once saturated, which is why it’s not ideal for intense outdoor exercise in cold weather.
Not All Cotton Is the Same
The quality of cotton fabric depends heavily on the length of the individual fibers, known as the staple length. Longer fibers can be spun into finer, smoother, and stronger yarns. Cotton varieties fall into three broad categories based on this measurement.
- Upland cotton is the workhorse of the industry, with staple lengths of 19 to 25 millimeters. It accounts for the vast majority of global production and is what you’ll find in most everyday clothing, bedsheets, and towels.
- Pima cotton has extra-long staple fibers ranging from 26 to 32 millimeters. Grown primarily in the southwestern United States and Peru, it produces a noticeably softer fabric with better color retention and durability.
- Egyptian cotton sits at the top of the range, with fibers stretching 32 to 50 millimeters. Those extra-long staples allow manufacturers to spin extremely fine yarns, which is how luxury sheets reach thread counts of 600 to 1,200 or more without feeling bulky. The resulting fabric has a smooth, slightly lustrous surface that resists pilling and gets softer with washing.
Soil minerals, climate, and growing conditions all influence the final character of the fiber. Peruvian Pima and American Pima, for instance, can differ in fineness and hand feel despite being the same species.
How Cotton Gets Graded
Before cotton reaches a textile mill, it goes through a standardized grading process. The USDA evaluates raw cotton on several measurable characteristics: color, leaf grade (how much plant debris remains), fiber length, strength, uniformity, micronaire (a measure of fiber fineness and maturity), and trash content. These grades determine pricing and which end products the cotton is suited for. Finer, stronger, cleaner cotton commands higher prices and ends up in premium fabrics, while lower grades go into industrial applications or blended materials.
Cotton Blends and What They Change
Pure cotton has well-known drawbacks: it wrinkles easily, shrinks in hot water, and wears out faster than synthetic alternatives. To address this, manufacturers frequently blend cotton with polyester. Cotton provides the comfort, moisture absorption, and soft hand feel. Polyester contributes wrinkle resistance, dimensional stability, abrasion resistance, and resistance to mildew and sunlight damage.
Blended fabrics also tend to pill less, hold their shape better through repeated washing, and dry faster than 100% cotton. A common blend ratio is 60% cotton and 40% polyester, though this varies depending on the intended use. Work uniforms, for example, often lean heavier on polyester for durability, while casual shirts typically favor a higher cotton percentage for comfort.
Global Production Scale
Cotton is grown on every inhabited continent. Global production for the 2025/26 season is projected at roughly 119.8 million bales. China leads at about 33.5 million bales (28% of the world total), followed by India at 24 million bales (20%). Brazil has emerged as a major producer, with output rising to a record 18.75 million bales. The United States rounds out the top four at nearly 14.3 million bales.
A single bale weighs about 480 pounds, so global production translates to roughly 57 billion pounds of raw cotton fiber each year. That fiber is cleaned, combed, spun into yarn, woven or knitted into fabric, and then dyed and finished before it becomes the material in your clothes, sheets, and towels.
Organic vs. Conventional Cotton
Organic cotton is chemically identical to conventional cotton. The difference is in how it’s grown: no synthetic pesticides, no genetically modified seeds, and soil fertility maintained through crop rotation and composting rather than chemical fertilizers. Two main certifications verify these claims. The Organic Content Standard (OCS) tracks the organic fiber through the supply chain. The Global Organic Textile Standard (GOTS) goes further, requiring that at least 70% of the fiber be organic, restricting which other fibers can be blended in, and imposing environmental and labor standards on the processing facilities themselves. If you see a GOTS label, it covers not just the farming but also the dyeing, finishing, and manufacturing stages.