T-Shirt Sizing and Fit: Reading a Size Chart Properly
A medium from one brand can be a large from another. The size chart, read the right way, tells you far more than the letter on the label.
T-shirt sizes are not standard. Letters like S, M and L mean different things from brand to brand, and the same brand can cut different styles differently. That is why returns for poor fit are so common, and why a merch seller who explains sizing well gets fewer complaints.
Measure a shirt you already like
The most reliable method is to lay a favourite T-shirt flat and measure it, then compare with the seller's chart. Two measurements matter most:
- Chest width: straight across, from armpit seam to armpit seam.
- Body length: from the highest point of the shoulder, next to the collar, down to the hem.
Some charts also give sleeve length and shoulder width. Check whether the chart lists garment measurements (the shirt itself) or body measurements (the person). Mixing them up is a common reason for ordering the wrong size.
Cuts and fits
- Classic or regular: straight body, room to move.
- Slim or fitted: narrower through the body, sometimes shorter sleeves.
- Oversized or boxy: wide body, dropped shoulders, often shorter length relative to width.
- Women's or fitted cut: shaped through the waist; sizing often runs smaller than unisex.
Allow for shrinkage
Shrinkage is the process in which a fabric becomes smaller than its original size, usually through washing. Pure cotton is more prone to it than polyester or many blends. If a blank is described as pre-shrunk, it should change less, but it may still change a little. When buying cotton shirts between two sizes, many people choose the larger.
For merch sellers: publish a useful chart
- Measure the actual blanks you will sell, not a generic chart from the internet.
- State that the figures are garment measurements laid flat.
- Give both units your buyers are likely to use.
- Add one sentence on fit, for example "relaxed unisex fit; size down for a closer fit".
- Mention whether the fabric may shrink.
Illustration only: if your favourite shirt measures a certain width across the chest and the chart's medium is noticeably wider while the small is a little narrower, the small will feel closer to what you already like. Compare widths, not letters.
Finally, if a buyer is unsure, a friendly reply with the exact measurement they asked about is worth more than any chart. It also tells you which sizing questions to answer on the page next time.
Petra Sandoval · revised 2026-11-09