Short answer: most T-shirts are made in six stages: fibre is spun into yarn, the yarn is knitted into jersey fabric, the fabric is dyed and finished, panels are cut, the panels are sewn with overlock and coverstitch machines, and the shirt is printed (if decorated), pressed and packed. The fabric is usually made by one company (a mill) and the shirt by another (a garment factory). This page explains each step and what happens at each seam.
If you are a brand specifying tees for production, see what to specify at each production stage. For woven shirts (dress shirts, button-downs), the process is different; see how shirts are made in the apparel industry.
1. Fibre to yarn
Cotton fibre is cleaned, carded (opened and aligned), optionally combed to remove short fibres, drawn into a sliver and spun into yarn. Ring spinning gives a finer, smoother yarn; open-end (rotor) spinning is faster and gives a slightly coarser hand. Combed, ring-spun yarn is common in softer tees; carded open-end yarn in budget and heavyweight basics. Polyester and blends start as manufactured filament or staple fibre. See combed versus carded jersey.
2. Yarn to fabric: knitting jersey
Most T-shirt fabric is single jersey, knitted on circular knitting machines that produce a tube of fabric. The tube can be finished as a tube (tubular) or slit open and finished flat (open width). Some basic tees use tubular fabric so the body has no side seams. Rib fabric for the neckband is knitted separately. See tubular or open-width knit.
3. Dyeing and finishing
Fabric is usually dyed after knitting (piece dyeing). Cotton is commonly dyed with reactive dyes and polyester with disperse dyes, so blends may need two dye stages. Finishing can include softening, brushing or peaching, and compacting, which pre-shrinks the fabric to reduce shrinkage in the finished shirt. Alternatively, finished undyed shirts can be garment-dyed. Fabric is then checked for weight, width, shade and shrinkage.
4. Cutting
Pattern pieces for every size (front, back, sleeves, neck rib) are arranged in a marker, the fabric is spread in layers, and the stack is cut with a straight knife or automated cutter. Pieces are numbered and bundled so each shirt is sewn from one layer, which keeps the shade consistent within a garment.
5. Sewing: the stitches at each part of the tee
Stitch types are classified in ISO 4915 by number. A typical knit tee uses:
| Part of the tee | Common stitch or seam | Why |
|---|---|---|
| Shoulder seams | Overlock (for example 4-thread, class 500), often with tape | Stretchy seam; tape limits shoulder stretch |
| Neck rib attachment | Overlock, then coverstitch or back-neck tape | Holds the rib and covers the seam |
| Sleeves set in | Overlock | Joins and neatens the edge in one pass |
| Side seams (if not tubular) | Overlock | Stretch with the fabric |
| Sleeve and body hems | Coverstitch (class 400 or 600, often two needles) | Flat, stretchy hem with a clean face |
| Labels | Lockstitch (class 300) or heat transfer | Fixed placement; tagless option |
These are common choices, not rules; factories vary, and premium or performance tees may use flatlock seams or bonding. Seam types themselves are classified in ISO 4916. Common faults at this stage include twisted side seams, wavy hems and needle holes; see spirality and twist and needle holes along hems.
6. Decoration, finishing and packing
Printing can be done on cut panels before sewing or on finished shirts. Screen printing, DTG, transfers and embroidery each suit different fabrics and order sizes; see sublimation or screen print. Shirts are then trimmed of loose threads, inspected, pressed, folded, labelled and packed.
Labels every tee needs
In the U.S., a tee must carry a fibre content and country-of-origin label and a care label (16 CFR Part 303 and Part 423). Fibres are named by generic name, for example “100% cotton” or “60% cotton, 40% polyester”.
How the steps affect the finished shirt
| If you notice… | The step it usually comes from |
|---|---|
| Shrinkage after washing | Finishing (compacting) and fabric construction |
| Side seams twisting | Knitting and finishing (spirality), cutting |
| Pilling | Yarn (fibre length, twist) and knit density |
| Neck stretching out | Rib fabric and neckband construction |
| Colour rubbing off | Dyeing and fixation |
Fact, advice and uncertainty
Fact: knit tees go through spinning, knitting, dyeing and finishing, cutting, sewing and finishing; the seams use standard stitch classes. Advice: if a tee fails, trace the fault to the stage that caused it before changing the specification. Uncertainty: stitch and finishing choices vary by factory and price point.
Knitwear Base makes knit T-shirts. For development see custom T-shirt development and the T-shirt products, or contact us through the contact page.
Sources and further reading
- ISO 4915:1991, Textiles: Stitch types, classification and terminology
- ISO 4916:1991, Textiles: Seam types, classification and terminology
- eCFR, 16 CFR Part 303, Rules under the Textile Fiber Products Identification Act
- eCFR, 16 CFR Part 423, Care Labeling of Textile Wearing Apparel
- AATCC TM135, Dimensional Changes of Fabrics after Home Laundering
- ISO 12945-2:2020, Fabric propensity to surface pilling, fuzzing or matting: modified Martindale method
Rules and standards are summarised from their official pages for general guidance; this is not legal advice. Check the current version and the requirements of your own market before you rely on them.
