Cotton T-Shirts: How to Specify One So the Bulk Matches the Sample
- Updated
In May 2026 a young Indian clothing brand did something most buyers never get round to. It bought six cotton fabrics, washed them over and over, and posted what happened. Its conclusion was blunt: "Higher GSM doesn't automatically mean better quality. The knitting quality, pre-shrinking process, and cotton itself matter way more." The 160 GSM regular cotton in the test "Shrunk noticeably after a few washes" (r/streetwearstartup, May 2026 (opens in a new tab)).
That's the whole problem with T-shirts in two sentences. The number everyone quotes is the one that tells you least. This page is about the other numbers, the ones that decide whether the thousandth shirt matches the one you approved. It works for any sourcing country. Our evidence is mostly Indian, so the examples are too, and the India-specific view (which towns, what each border charges) lives on cotton T-shirts from India. One caveat. Nobody publishes a standard T-shirt spec, and we haven't found an official one, so what follows is what makers and buyers say goes wrong, turned into lines you can write down.
The Spec, Line By Line
Here's what a T-shirt spec needs, and why each line is there. It's the one place on this page where a table earns its keep, because you'll copy these rows into your own tech pack.
| Spec line | What to write | Why it's there |
|---|---|---|
| Fibre and yarn | 100% cotton or the blend by weight, combed or carded, ring-spun or open-end, and the yarn count | A Tiruppur exporter put it plainly: "There is no standard as Tiruppur quality" (r/indianstartups, 2024 (opens in a new tab)). The yarn is where quality is decided, not the town |
| Knit | Single jersey, rib, interlock or slub, and tubular or open-width | Tubular knits are made to a set body width, which is why the trade talks in Dia |
| Fabric weight | GSM with a tolerance, measured on raw, unwashed fabric and again after washing | Starch and stiffeners wash out. A GSM figure with no test condition is a figure you can't enforce |
| Shrinkage | Maximum length and width shrinkage after a stated number of washes | 3% is one working buyer's limit. Pick yours and tie a payment to it |
| Finish | Bio-wash, enzyme wash, silicone softener, compacting or pre-shrinking | The finish changes hand-feel and shrinkage, and it's the step most often skipped on small runs |
| Colour | Dye method, a physical colour standard and the light source you'll judge it under | Knitting, dyeing and printing are often separate units, so dye lots drift between batches |
| Method (water-based, plastisol, discharge, DTG) and the restricted substances you'll test for | Plastisol prints are where phthalates turn up | |
| Size chart | Your measurements in centimetres, with tolerances, plus the maker's own size names | Convert your chart into the maker's system before quoting, not after |
| Neck and seams | Neck rib height, taping, stitch type and stitches per inch | These are what a customer notices after ten washes |
| Labels | Fibre content, care symbols, country of origin and your brand label, in the wording your market requires | Label rules are national, so the maker needs yours in writing |
| Children's styles | No functional cords at neck or hood, and whether any style is sold as sleepwear | Design faults, not dyes, cause most children's clothing recalls |
Two of those rows deserve a story each.
The colour row. A buying agent who worked for US and European brands described big suppliers keeping "1 big shiny beautiful factory for the audits and inspections" (r/IAmA, 2013 (opens in a new tab)). It's an old remark, and it's not a charge against anyone. Splitting knitting, dyeing and printing across specialist units is how T-shirt towns everywhere stay efficient. It does mean the unit you visit may not dye your fabric. So ask which unit dyes, and ask for a lot number on every roll.
The size row. In Tiruppur the trade has long quoted a medium as roughly a 17-inch Dia chest and a 26-inch length (Quora, about 2018 (opens in a new tab)). That's a convention, not a promise, and it's one old source. The point stands anyway. If you send "M" and the maker reads "17 Dia", you have two size charts and no agreement. Send measurements.
When the spec is written, put it into a request for quote with the RFQ template, and judge the first sample against it with the sample evaluation checklist.
Knitted Or Not: How A T-Shirt Is Classified
At the border a T-shirt is heading 6109, "T-shirts, singlets and other vests, knitted or crocheted". Cotton ones sit in 6109.10 and other fibres in 6109.90. Three things move a shirt out of that line, and each one is a spec decision.
The first is the fabric. A "tee" cut from woven cotton isn't a 6109 garment at all, because the heading is for knits. It's a woven shirt or blouse, with a different line and often a different rate. The second is the blend. A shirt is classified by the fibre that's heaviest by weight, so a 50/50 cotton-polyester tee can tip into 6109.90 depending on the exact split. Write the percentage by weight into the spec and on the invoice. The third is the style. A long-sleeved knitted top with a collar and a part-button front may read as a polo or a shirt rather than a T-shirt.
Rates differ a lot by market. The UK, for example, charges 12% on a cotton T-shirt from a country with no preference, and 0% on one from India with proof of origin (UK tariff, 6109100010 (opens in a new tab), read 5 Oct 2026). The method is on finding your HS code, and whether a sewn-in-India shirt counts as Indian under a trade deal is on rules of origin. The fabric's origin is often the deciding fact. Your customs broker should confirm the 10-digit line before you price.
What Gets Tested, Market By Market
Across the official recall and alert lists we pulled for India-origin goods from 2021 to September 2026 (EU Safety Gate, UK product safety reports and US CPSC recalls), we found no case naming a plain adult cotton T-shirt. The failures cluster in three places, and they're the same three wherever you source.
Europe and the UK test the chemistry. Azo dyes that release banned amines are restricted to 30 mg/kg in textiles that touch the skin (Regulation 552/2009 (opens in a new tab)). Phthalates are restricted in plastic parts and plastisol prints. For children's wear, the cord rules in EN 14682 are where most alerts on Indian clothing come from. If your tee has a hood or a neck tie, show the pattern to your lab before the sample is cut.
The US tests children's products as a category. Anything made for children aged 12 or under needs total lead in accessible parts at 100 ppm or less, and paint or coatings at 0.009% (CPSC (opens in a new tab)), with a Children's Product Certificate based on a third-party test. Then there's the trap in our third intelligence point. A cotton tee sold on its own is ordinary apparel. Put it in a pyjama or loungewear set for a child and it can become children's sleepwear, with its own flammability rules. The way out that the recall analysis points to is a design choice made early, either a tight-fitting cut or a fabric that passes the flammability test. India-made loungewear sets were recalled for exactly that in 2025 and 2026 (CPSC, 2026 (opens in a new tab), CPSC, 2025 (opens in a new tab)). Decide how the shirt will be marketed before the maker cuts it.
Everyone should test what the lab can't see in an inspection. An AQL inspection counts visible defects on a sample of finished cartons. It won't tell you the fabric is 20 GSM light or that the shirt will lose two centimetres in the wash. Those are lab and wash tests, and they belong in the purchase order. If you sell organic, the certificate that matters is the one for your shipment, which textile certifications explains.
Where T-Shirts Are Made
Most countries that make clothing make T-shirts, so the real question is who makes the shirt you need. In India the answer is short. Knits mean Tiruppur, knitted winterwear means Ludhiana, and if your range also has woven shirts, the Delhi apparel belt is the place to look. Which Indian town, what each border charges on an Indian tee and which origin proof you'll need are all on cotton T-shirts from India. For the plain basic at scale, India against Bangladesh is the honest comparison. The wider family, from knitwear to home textiles, is on textiles, and if you're putting your own brand on the shirt, private label covers what you add.
Ready to act
Need hands-on help?
Weighing raw fabric at the mill, watching the wash test and measuring bulk against your chart is work on the factory floor. SourcingSync does it at origin.
Questions Buyers Ask
Is a heavier T-shirt a better T-shirt?
Not by itself. Weight is one line in the spec. Yarn, knit, finish and pre-shrinking decide how the shirt wears, which is what the brand in our opening found when it washed six fabrics side by side.
What shrinkage should I accept?
There's no official figure we could find. One buyer working in Indian factories uses 3% after washing and ties the final payment to it. Choose a number your customers will tolerate, write the wash method next to it, and test it on bulk, not on the sample.
Does a cotton-polyester tee have the same HS code as a cotton one?
Only if cotton is still the heaviest fibre by weight. If polyester is heavier, it moves to 6109.90. Ask your customs broker to confirm the line with the blend on the invoice.
Back To The Six Fabrics
The brand that washed six fabrics didn't need a lab or an agent to learn the lesson. It needed a bucket and some patience. That's the spirit of a good T-shirt spec. Every line on it is something you can check yourself, raw and washed, before the bulk is cut, and once each line is written, the maker you choose has something to promise you.