Buying an oversized tee online is trickier than it sounds. Regular sizing logic doesn't apply, and going by your usual size can leave you with a shirt that's either too tight to look intentional or so big it swallows you.

Start with the chest measurement, not your usual t-shirt size. Oversized fits are designed with extra room built in, so a size M in an oversized cut is not the same shirt as a size M in a regular fit. Most product pages list a body measurement chart alongside the garment measurement, like the one on the illegal tee. Compare your actual chest and shoulder width to the garment width, not just the label.

A good rule of thumb: for a proper oversized drop, you want two to four inches of extra room across the chest compared to your regular fit. Any less and it just looks like a regular tee that shrank the wrong way. Any more and you risk it looking like a nightshirt.

Shoulder drop is the detail most people skip. This is where the seam sits below your actual shoulder point. A small drop keeps things wearable for daily use. A bigger drop gives that dropped, boxy streetwear look but works best on people comfortable with a looser silhouette overall, like the boxy cut on the Diet Coke Boxy Fit tee.

Fabric weight changes how a size feels too. A heavier cotton drapes differently than a lighter blend, so the same size label can fit two different ways depending on the fabric.

If you're between two sizes, size up if you plan to layer the tee or wear it as a standalone statement piece, and size down slightly if you want a cleaner, half tuck friendly drop. When in doubt, check the size chart listed on each product page rather than assuming your usual size carries over.