A - Bust
Measure your chest around the fullest part of your bust while wearing a bra that fits well.
B - Waist
Measure the narrowest part of your waistline.
C - Hips
Measure the fullest part of your hips,  approx 4cm above the crotch.

 

Measurements in cm's

Bust Waist Hips UK
XS 79 63 88 6
S 84 68 93 8
M 89 73 98 10
L 94 78 103 12
XL 99 83 108 14