How to Build a T-Shirt Size Chart for US and EU Buyers

A size chart looks like the simplest document in a tech pack. A grid of sizes, a few measurements, done. Yet more bulk orders disappoint over sizing than over any other single cause: the medium that fits like a large, the body length that crept up, the women’s range graded from a men’s block by guesswork. When that happens, the factory usually sewed exactly what the chart said. The chart itself was the problem.

We produce t-shirts for buyers across the USA, UK, Europe, Canada, Australia and the Middle East, and the size charts that work share the same foundations. This guide sets them out: which measurements matter, how factories actually measure a garment, how US and EU conventions differ, how sizes step between each other, and what tolerance to allow so production is judged fairly and consistently.

The Five Measurements That Define a T-Shirt

Every workable t-shirt chart is built on five core measurements. Chest width, taken flat across the garment, decides the fit more than any other number. Body length, from the highest point of the shoulder to the hem, sets the silhouette and how the shirt tucks. Sleeve length shapes the style, short and neat or long and relaxed. Shoulder width controls how the sleeve seam sits on the body. Neck opening and collar depth decide whether the shirt feels polished or sloppy at the throat.

Everything else is refinement. Armhole depth, sleeve opening, hem width and collar width all help a factory sew accurately, and a complete tech pack should carry them, but if the five core numbers are right, the shirt fits. If the chest is wrong, no amount of detail elsewhere saves it. Our advice to new buyers is to spend their argument time on those five, size by size, and let the secondary measurements follow standard relationships from them.

One discipline matters throughout: state whether your numbers are garment measurements or body measurements. Factories work in garment measurements, the actual centimetres of cloth. Retail charts often quote body measurements, the person the size is meant for. The gap between the two is the wearing ease, and confusing the systems is the single most common sizing error we see in first tech packs.

How Factories Measure, So Your Numbers Mean the Same Thing

A measurement is only useful if both sides take it the same way. In production, chest width is measured flat, straight across the garment, 2.5 centimetres below the armhole seam, then doubled by some factories and quoted flat by others, so the method must be written on the chart. Body length is measured from the highest point of the shoulder, beside the collar, straight down to the hem, not from the centre back neck unless the chart says so.

Sleeve length runs from the shoulder point to the sleeve hem along the top edge. Shoulder is measured seam to seam across the back. These small definitions sound pedantic until a buyer’s sample arrives two centimetres longer than expected and both sides are holding rulers, each honestly measuring a different line. Professional charts include a simple measurement diagram, a sketch of the shirt with lettered points matching the chart rows. It takes an hour to prepare and prevents the most expensive misunderstandings in the business.

All of this is verified physically, not on paper. At the pre-production stage we sew and measure a full size set, every size in the range, and report actual measurements against the chart before bulk cutting. That step is built into our normal sampling flow, which our MOQ and production page describes alongside the minimums: 1,200 pieces per style in up to two colours.

US and EU Sizing: Two Habits, One Garment

American and European buyers describe the same shirt differently. US ranges are usually lettered S to 3XL, cut a little more generously, with longer bodies as standard. EU retail more often pairs letters with numeric sizes, 46 to 60 for men, and expects a closer fit through the body. UK practice sits close to the US pattern but with its own expectations on length. None of these is a fixed standard: a US medium from one brand can equal an EU large from another.

That is why conversions should always be built from measurements, never from letter labels. A conversion table that says “US M = EU 50” is a starting guess; a chart that says “chest 104 centimetres” is an instruction a factory can sew to. If you sell into both markets, keep one master measurement chart in centimetres, then publish market-facing versions that present it in inches for the USA and in local numeric sizes for Europe. The garment never changes, only the label story.

Dual labelling helps at the warehouse too. Many of our buyers print both letter and numeric sizes on the neck label or the polybag sticker, so the same stock can serve a US distributor and an EU retailer without repacking. Decide that at the tech pack stage, not when the cartons are being sealed.

Grading: How Sizes Step From One to the Next

Grading is the set of steps between sizes. For adult t-shirts, a common pattern steps the chest by 5 centimetres of full circumference (2.5 centimetres flat) between sizes, body length by 2 centimetres, sleeve length by half to 1 centimetre, and shoulder by about 1 centimetre. Larger sizes often grade slightly wider per step than core sizes, because bodies change shape as well as scale, and good graders adjust armhole and neck along with the headline numbers.

Where buyers go wrong is approving one perfect sample size, usually a medium, and letting the factory extrapolate the rest silently. A size set exists to prevent that. Approve the steps in writing, sew the full set, measure every size, and only then cut bulk. The cost is a few extra samples; the protection is discovering that your 2XL has a collar like a medium before 1,200 pieces exist with that collar.

Women’s and youth ranges need their own grading logic rather than scaled copies of the men’s chart. Women’s grades step differently at the bust and waist, and lengths run shorter; our Women’s Fit T-Shirt is graded on its own block for that reason. Youth sizes step by age bands with smaller increments, as the Youth T-Shirt range does. Children also grow through sizes faster, so buyers often widen the steps slightly and accept a relaxed fit that lasts the season.

Tolerances: The Allowance That Keeps Production Honest

No factory sews a thousand shirts to the exact tenth of a centimetre, and no honest chart pretends otherwise. Tolerances state the accepted variation, commonly plus or minus 1 centimetre on body length and sleeve length, and plus or minus 1 to 1.5 centimetres on chest width for knitted garments, which move more than wovens. Setting them is not lowering standards. It is defining the standard in a way that can be measured, enforced and passed.

Tolerances also interact with fabric behaviour. A cotton jersey shirt measured straight off the machine will relax slightly after washing, which is why inspection often measures after a wash test, and why fabric choice belongs in the sizing conversation. The shrinkage differences between fibre routes are covered in our cotton versus blend comparison, and they explain why the same chart can yield a firmer fit in a blend and a softer one in pure cotton. Build the expected wash behaviour into the chart targets from the start, aiming at the after-wash measurements your customer will actually judge.

T-Shirt Size Chart Mistakes That Reach Production

The first is copying a competitor’s retail chart. Those charts describe body sizes for marketing, often rounded generously, and sewing to them produces garments a full size larger than intended. The second is mixing units mid-chart, inches for chest and centimetres for length, which guarantees a conversion error somewhere between the buyer’s desk and the cutting table. Pick one unit for the master chart; we work in centimetres, as does most of the world’s production.

The third is freezing the chart before the fit sample and never updating it. Fit approval almost always changes something, a centimetre of length, a touch of chest ease, and if those changes live only in an email thread, the bulk will be sewn to the old numbers. The rule is simple: whatever was approved on the final sample is what the final chart must say, revised and reissued the same week.

Putting the Size Chart in Your T-Shirt Tech Pack

A chart that lives in a spreadsheet nobody opens protects nobody. In a complete tech pack, the size chart sits with the measurement diagram, the fabric specification, the construction notes and the artwork, all under one revision number. When anything changes, the revision changes, and the sample room works from the newest copy only. Most sizing disasters we are asked to rescue trace back to two versions of a chart circulating at once.

Include three practical items alongside the numbers. First, the base size, the size your fit sample was approved in, clearly marked. Second, the measurement method for every row, in words short enough to fit the chart itself. Third, your tolerance column, printed, not implied. With those in place, a buyer in Chicago and a pattern master in Dhaka are reading the same document, and the pre-production size set becomes a confirmation instead of an argument. Buyers who want the fabric groundwork first will find it in our t-shirt fabrics guide, since the knit structure you choose changes how a garment measures and relaxes.

Do this properly once and the chart becomes an asset: reorders run from it unchanged, new styles inherit its grading, and your customers learn that your medium is always your medium. In a business built on repeat orders, that consistency quietly sells.

Frequently Asked Questions