A t-shirt is the simplest thing most people own, and one of the easiest to get slightly wrong. A few details decide whether it looks like it was made for you or borrowed from someone else.
Shoulders
Start here, because it is the one thing a tailor cannot easily fix. On a regular fit t-shirt, the shoulder seam should sit at the edge of your shoulder, right where your arm begins. If the seam hangs down your upper arm, the shirt is too big. If it sits up on the top of your shoulder, it is too small.
The exception is an oversized or drop shoulder style, where the seam is designed to sit lower. Those are cut that way on purpose, so judge them by the rest of the fit.
Chest
You should be able to pinch a little fabric at the side of your chest, roughly a couple of centimetres. If the fabric pulls across your chest, or you can see lines stretching from your armpits, it is too tight. If there is a lot of loose fabric billowing around your middle, it is too big.
In numbers, a regular fit t-shirt usually measures somewhat more round the chest than your body does. That extra room is called ease, and slim fits have less of it while relaxed fits have more. When a brand publishes garment measurements, compare the garment chest with your own chest to see how much room you will have.
Length
The hem should land around the middle of your trouser fly or zip. That covers your waistband when you raise your arms without being long enough to bunch up. A t-shirt that shows your stomach when you reach up is too short; one that covers your pockets is too long, unless it is meant to be.
Sleeves
Short sleeves should finish around the middle of your upper arm and sit fairly close to it without squeezing. Sleeves that flare out widely or hang towards your elbow usually mean the shirt is a size too big.
Neck
A crew neck should sit flat against the base of your neck, close but not tight. A neckline that has stretched and gone wavy is a sign of a worn out shirt, or of cotton that was too thin to begin with.
Fabric changes the fit
- 100% cotton can shrink a little in the first hot wash or tumble dry. If you are between sizes, the larger one gives you margin.
- Cotton with elastane stretches and recovers, so it can be worn closer to the body.
- Heavyweight cotton hangs straighter and hides more, which suits a boxier fit.
Regular, slim, relaxed and oversized
- Slim: close to the body through the chest and waist, with the least ease.
- Regular: a comfortable, classic fit with a little room.
- Relaxed: more room through the body, but shoulders still roughly in place.
- Oversized: deliberately large, with dropped shoulders and a longer, wider body.
Pick the style on purpose, then size to your measurements for that style rather than sizing up or down to fake a different fit.
Get it right before it arrives
Check the chest and length on the brand's chart against your own measurements before you buy. clothly does it for you from a screenshot of the listing, and shows the shirt on a model built to your body so you can see the fit, not just read about it.