Bra Size Converter

Bra sizes vary by country. Each system uses different band numbering and cup letter schemes.

Band size conversions:

Cup size conversions

All three systems agree up to D and then go their own ways, which is where almost every mis-sized order comes from. Lined up as equivalents rather than as separate lists:

A UK E is not an EU E. UK E is the sixth cup up, EU E is the fifth. Reading across the rows above is the only safe way to do it, and the same letter appearing in two systems is a coincidence rather than a match.

How band sizes relate:

• EU band = (US band − 4) × 2.54, rounded to the nearest 5
• French band = EU band + 15
• Australian band = US band − 22
• Japanese band = the same as the EU band

That −4 matters. A US 34 band is an EU 75, not the 86 you get from multiplying by 2.54 alone, because the US band number is not the raw underbust measurement: it already has roughly four inches of ease built into it, while the EU number is the underbust in centimetres.

Measurement method:

1. Measure snugly under the bust. That figure in inches, rounded, is close to your US band.
2. Measure around the fullest part of the bust, loosely.
3. Subtract the first from the second. Each inch of difference is one cup: 1 inch is an A, 2 a B, 3 a C, and so on up.

The calculator below does step 3 for you. Note that this “difference method” gets less reliable above about a 5-inch difference, and that band and cup are linked: go down a band size and you need to go up a cup to keep the same volume, which is why 34C and 32D hold the same amount.