If you have gone looking for a shirt inseam and come up empty, there is a reason. A shirt does not have one, at least not in the sense a pair of trousers does.
An inseam is the seam running down the inside of a trouser leg, from the crotch to the hem. A shirt has no crotch and no legs, so the measurement has nowhere to live. What people usually want when they search for it is one of four other figures, and this covers all of them.
Why the question comes up at all
Two reasons, and both are reasonable.
The first is that trouser sizing trains you to think in inseams, so the word travels with you to the next size chart. The second is that shirts genuinely do have an inside seam, on the sleeve, and some tailors call it the under-sleeve or sleeve inseam.
The one seam on a shirt that behaves like an inseam
Run a finger along the underside of a sleeve. The seam from the armpit down to the cuff is the closest thing a shirt has to an inseam, and tailors do measure it.
To take it, lay the shirt flat with the sleeve smoothed out and straight. Put the tape at the point where the sleeve seam meets the side seam, then run it along the underside of the sleeve to the edge of the cuff.
It is a useful figure if you are having a shirt altered. It is close to useless for buying one off the shelf, because nobody publishes it.
The four measurements that decide whether a shirt fits
These are what size charts actually give you, and between them they describe the garment completely.
- Body length. Highest point of the shoulder straight down to the hem. Decides whether it tucks, covers, or sits short.
- Chest. Measured flat across, armpit to armpit, then doubled to give a circumference. Decides room through the body.
- Shoulder. Straight across the back from one shoulder seam to the other. Decides where the sleeve head sits on your arm.
- Sleeve. Shoulder seam out to the cuff. Decides where the cuff lands on your wrist.
Shoulder is the one to check first. Chest and length can be forgiven by a loose cut, but a shoulder seam sitting in the wrong place is visible from across a room and no amount of fabric fixes it.
How to take each one
Work on a flat table, with the shirt buttoned where it has buttons, and smooth out every crease before the tape goes down.
- Length. Find the highest point of the shoulder next to the collar, then measure straight down to the bottom hem. Do not follow the curve of a dropped tail.
- Chest. Measure straight across from one armpit seam to the other. Double it for the circumference figure charts usually quote.
- Shoulder. Measure across the back, seam to seam, in a straight line rather than over the curve.
- Sleeve. Measure from the shoulder seam along the top of the sleeve to the cuff edge.
Take each figure twice. If the two readings differ, the shirt was not lying flat.
The sleeve trap
Sleeve length is quoted two entirely different ways, and mixing them up costs you about 30 cm.
Dress shirt sizing often measures from the centre of the back neck, over the shoulder, and down to the cuff. Flat garment charts measure from the shoulder seam only. The first gives you something near 85 cm on an adult shirt, the second something near 56 cm.
You can tell which convention a chart uses by comparing the sleeve figure to the shoulder figure. The Oversized Long-Sleeve Cotton-Blend T-Shirt lists a 55 cm shoulder against a 56.5 cm sleeve at M. Two numbers that close can only be a shoulder-seam measurement, because a centre-back figure would be half as long again.
What a shirt chart looks like in practice
Every Amaji product page carries the manufacturer's own flat measurement chart for that garment, transcribed and converted to centimetres. Of the 98 charts on the site, 66 give a chest figure, 65 give a sleeve, 46 give a shoulder and 90 give a body length. None gives an inseam.
A short-sleeve chart reads much the same with smaller sleeve figures. The Honeycomb Tech T-Shirt lists 106 cm chest, 47 cm shoulder, 21 cm sleeve and 68 cm length at S.
Our how we measure page sets out what each column describes, where the figures come from, and how much tolerance to allow. Expect 2 cm to 3 cm of variation on any single figure, and rather more on a knit than on a woven cloth.
The shortcut that beats all of this
Take a shirt you already own and like the fit of, lay it flat, and measure those four points. Write them down.
From then on you are comparing a garment against a garment rather than a body against a chart, which removes every guess about how a brand expects its clothes to sit. It is the single most reliable thing you can do about sizing, and it takes five minutes once.
Where to go next
For the measurement shirts genuinely do not have, see where the inseam is on pants and length versus inseam. Fabric weight changes how a tee hangs at any size, which t-shirt GSM explained covers. Browse shirts and t-shirts.