Band size

Band size is the number in a bra size: the 75 in 75C, the 34 in 34C. It comes from the underbust, the ribcage just under the bust. Under EN 13402-3, the European band is the underbust rounded to the nearest 5 cm, so an underbust of 76 cm is a 75 band.

How to find it

1. Measure your underbust snugly, the tape level, just under the bust.
2. Round it to the nearest 5 cm: that is the EU band.
3. Read the other systems from the table below.

On a size chart

Each 5 cm step of the EU band is 2 band numbers in the UK, the US and Australia. France adds 15 to the EU band, Italy counts steps from 60, and Japan writes the cup first. Here with a C cup:

The Bras template gives each of its bands an underbust range: 70 for 68 to 72 cm, 75 for 73 to 77 cm, 80 for 78 to 82 cm, each band cell merged across its four cups.

In Ruban Size

On a bra chart, Find my size weighs the underbust most and answers with a size from the chart, followed by "The same size in other systems" and the sister sizes. A band too loose counts against a size as much as one too tight. Size systems sit on their own rows, with a switch for shoppers and a default by country: US for the United States, UK for Great Britain and Ireland, EU elsewhere. The bra size calculator does the rounding for you.