Bra Size Calculator

Two measurements, ideally unpadded or braless: underbust — snug (not tight) directly under the bust, tape level all the way around, exhale normally; and bust — around the fullest point, tape level and resting on the body without compressing. Standing relaxed, in front of a mirror to check the tape isn't riding up in back. Small technique errors move the result a full size, which is one honest reason the same person gets different answers from different calculators.

Because the old method added 4 inches to the underbust — a relic of non-stretch fabrics — and much of the industry quietly kept it, which is how 'most people wear the wrong size' became a fitting-room cliché. Modern elastic bands are meant to sit at roughly your actual underbust: the band provides about 80% of the support, and it can only do that if it's snug. A firm band with a larger cup feels dramatically different from the loose-band-small-cup combination it replaces.

Sizes with the same cup volume on different bands: 34C, 32D, and 36B all hold the same amount — cup letters are relative to their band, which is the single most misunderstood fact in bra sizing (a D cup isn't one size). Use them to translate between brands that run tight or loose: band riding up your back → go down a band, up a cup letter; band digging in on the loosest hook → the reverse. The calculator lists yours automatically.

Trust the fit checks over the number, in this order: the band should sit level front to back and feel firm on the loosest hook (you tighten hooks as it stretches with age); the center panel should lie flat against your sternum; no spillover or gaping at the cup. Gaping cup → smaller cup or different style; center panel floating → larger cup. Breast shape (projection, fullness) matters as much as volume, which is why two people with identical measurements can need different styles. Calculators start the search; mirrors finish it.