Our swimsuits are catered to small chests which is 1-4 inch difference between your underbust and bust measurement.
E.g. 30" underbust and 31" bust (1" difference)
E.g. 28" underbust and 32" bust (4" difference)
If you are 5-6 inch difference, we recommend you sizing up one size.
E.g. 30" underbust and 36" bust (6" difference) we recommend sizing up from size S to size M.
Unfortunately the styles and fit are less suitable for chests with a 7+ inch difference.