From WACOAL.PH website
TAKING YOUR MEASUREMENTS
TO KNOW YOUR BRA SIZE
Measure your underbust (in cm.) by wrapping the measuring tape around the lowest part of the bust (verge line). Make sure the tape measure is parallel to the floor.
Measure your top bust (in cm.) by wrapping the tape measure around the peak point of your bust.
Cup size is determined by getting the difference between the top bust and the underbust.
|Underbust||77cm||= 75 underbust|
|Difference||16cm||= cup C|
Measure the highest point of your hips.
Measure the slimmest point of your waist and highest part of your hips.
For example, waist measurement falls on size 64 and hip measurement falls on size 72, choose the bigger size which is size 72.
Note: Something small can always fit into something big but something big cannot fit into something small.