Model is 5'6" and a UK8, she likes a relaxed fit and so she chose to size up to a 'Medium' in this t-shirt.
XS: 32-34" Chest (UK 8-10)
S: 34/36" Chest (UK 10-12)
M: 38/40" Chest (UK 12-14)
L: 42/44" Chest (UK 14-16)
XL: 46/48" Chest (UK 18-20)
All sizes are approximate, if you would like any more information please feel free to get in touch with us via the ‘ask the seller a question’ button at the top of the item description and we'll get back to you as soon as we can.