Getting the perfect fit is easy. Just grab your favourite tee shirt, lay it flat on a table, take a few measurements and pick the closest matching shirt. If you are in between 2 sizes always go on the larger, chances are your favourite tee has shrunk a little since you got it. Shirt sizes can vary by +/- 3cm, and will shrink by 1-3 cm over time. If in doubt, go on the bigger size! WOMEN (especially in the US and UK) Some customers say our shirts fit small compared to what they are used to (sometimes called Junior fit) so you may need to order up 1-2 sizes from usual. If in doubt compare to a tee you own that fit you. Thanks!