XS   S   M   L XL
Waist 12" 13" 14" 15" 16"
Hip 17" 18" 19" 20" 21"
Rise 14.5" 15" 15.5" 16" 16.5"
Length 31.5" 32" 32.5" 33" 33.5"

*Model is 1.73m, UK 4/6 (PTP15.5", Waist 12", Hips 17.25") wears size XS.

If you are in between size for hip, it is best recommended to size up. 

If you are in between size for waist, you can choose to size down if you would like to wear it higher-waist, otherwise you can size up to wear it lower-waist.

*In between sizes refers to your measurements falling between 2 sizes, example size S & M.