Fabric weight, measured in GSM (grams per square metre), tells you a lot about how a t-shirt will feel and perform. Heavyweight tees, generally 200 GSM and above, feel sturdier, hold their shape better after washing, and drape with a more structured look — popular in premium streetwear. Lightweight tees, usually under 160 GSM, are thinner, more breathable, and better suited to warm weather or layering.
Neither weight is better overall; it depends on how and when you'll wear the tee. Heavyweight cotton is a great pick for year-round streetwear staples that need to last, while lightweight fabric is ideal for summer days or wearing under jackets and hoodies without adding bulk. If you're unsure, a mid-weight tee around 180 GSM offers a solid balance of durability and comfort.