"Underbust Width (laid flat)" is measured horizontally across one side of the garment when laid flat, at the supportive area beneath the bust, and does not include any protrusion from the bust cup; for a full circumference reference, multiply the value by 2 (as shown in "Approx. Total Underbust Circ." above). All measurements above are taken with the garment laid flat.

When measuring, customers should use a soft tape measure to wrap around their underbust (below the breasts, snug against the ribs), keeping it level and slightly taut, to get their underbust measurement. Size 9 is suitable for an underbust of approx. 66–72cm; Size 11 is suitable for an underbust of approx. 72–76cm.

Since this style has a close-fitting design with no elasticated back strap, there is less overall adjustability; if you are between two sizes or prefer a more comfortable fit without the underbust area being too tight, it is recommended to choose the larger size. If you have a slender figure and desire a more snug and sleek look, you may opt for a smaller size.