honestly winged it when i brought these for partner he is usually a large but after reading guide i decided to get him a medium and honestly it looks like a oversize fit on him anyway so sizing was absolutely fantastic. The quality of the T-shirt as well is so nice and thick and it has with-stood over two weeks worth of washing already being worn every second day and the colour of the print on the back has not faded one bit. I highly recommend will be buying from you again.