These are the body measurements of each size and do not indicate the dimensions of the garment.
About 2-3 inches are added to each body measurement to get the right fit and comfort depending on the style of the garment.
Please use the below chart to find your perfect fit. While an XS is approximately a UK 8, and an S a UK 10 etc. there is no such thing as standard sizing and the only way to be sure the dress will fit is to measure yourself.
For the chest, please measure around your bust at the fullest part,