Ever bought "your size" from a new brand and had it fit completely differently? You're not imagining it, and it's not a fluke. Bra sizing isn't standardised the way you'd expect — every brand cuts, constructs, and shapes their bras a little differently, even when the label says the same number.

Band Size Stays Fairly Consistent

• Band size is measured the same way across most brands — firmly around your ribcage, directly under the bust.
• The numbers tend to translate reliably — a 14 or 16 band from one brand is usually close to the same from another.

Cup Size Is Where It Shifts

Cup size is where things genuinely diverge between brands. Two bras labelled the same cup letter can fit completely differently depending on how that brand cuts and constructs its cups — and this gets more noticeable the further up the cup range you go, which is exactly where full-bust sizing lives.

• Cup volume isn't standardised — brands calculate and shape cups differently, even at the "same" letter.
• Cup shape varies too — a balconette, full cup, and plunge style all sit differently even in your usual size.
• The gap widens at larger sizes — small differences in cup construction become more noticeable the fuller the bust.

Why Construction Matters Too

• Wire shape — a deeper or shallower wire changes how the cup sits, even at the same size.
• Fabric stretch — stretch lace, rigid moulded cups, and structured satin all behave differently on the body.
• Cup depth — some brands cut generously, others run shallow, regardless of the labelled size.

How To Shop Smart Across Brands

The fix isn't finding "the right size" once and sticking to it forever across every brand — it's checking each brand's own size chart before you buy, especially when trying something new. If a style runs differently to what you're used to, that's normal, not a sign you measured wrong.

Frequently Asked Questions