Oversized is a cut, not a size. A boxy tee is already designed with extra room, so most people should stay in their usual size and only go up one size if they want a very loose look. Start from the size chart, not the label Measure the widest part of your chest and compare it with the chest column on the product's size chart. If you are between two sizes, ask yourself how you want it to fall. A quick rule Want the look as designed: take your usual size. Want it slouchier: go one size up. Layering under a jacket: stay in your usual size. Trousers Check the waist and the length. Baggy trousers can be worn low or high, so the waist matters more than the label. Not sure? Use "Find my size" on any product page.