Bra Size Calculator
This calculator estimates bra size based on bust size and band size (frame size). To ensure accuracy, measure to the nearest ¼ inch or ½ cm. This calculator provides results for the United States, the United Kingdom, European Union, France, Belgium, Spain, Australia, and New Zealand.
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The bust size is the loose circumference measured around the chest over the fullest part of the breasts, while standing straight with arms to the side, and wearing a properly fitted bra.
The band or frame size is the firm circumference, fitted not tightly, measured directly underneath the breasts.
Bra Size Converter
Use the following to convert the bra sizes between different locations.
Incorrect bra fit
Research consistently shows that a large majority—estimates ranging from 70% up to 85%—of women wear bras that don't fit properly. Although survey methods differ and the exact figure may be exaggerated, the problem is clearly significant, as reflected by numerous studies, articles and consumer complaints about the lack of size standardisation. The most frequent fitting error is choosing a band that's too loose while picking cups that are too tight. The root cause lies in the absence of a universal sizing system; band and cup measurements differ widely between countries and even between brands. Consequently, a 34B from one maker may feel completely different from a 34B from another.
Some signs of incorrectly fitted bras include the band digging into the torso or sliding upwards, red marks, shoulder or neck pain, the breasts overflowing around the edges of the bra, and the bra's center panel not lying flat against the breast, among others.
Bra size
The two major aspects of bra size are the band size and the cup size.
Band size (frame size)
Band size refers to the measurement of the band that wraps around the torso. These measurements are not uniform worldwide – terms such as small, medium or large correspond to different actual dimensions depending on the market. See the table below for typical values, keeping in mind that some manufacturers may deviate slightly from the listed figures.
| Band Size | FR/BE/ES | EU (Standard EN 13402) | US and UK | AU, NZ |
| XXS | 75 | 60 | 28 | 6 |
| XS | 80 | 65 | 30 | 8 |
| S | 85 | 70 | 32 | 10 |
| M | 90 | 75 | 34 | 12 |
| L | 95 | 80 | 36 | 14 |
| XL | 100 | 85 | 38 | 16 |
| XXL | 105 | 90 | 40 | 18 |
| 3XL | 110 | 95 | 42 | 20 |
| 4XL | 115 | 100 | 44 | 22 |
| 5XL | 120 | 105 | 46 | 24 |
Cup size
Cup size is derived from the difference between the bust measurement and the band size. The following table illustrates how this gap translates into cup letters.
| Bust/band difference in inches | US cup size | UK/AU cup size |
| <1 | AA | AA |
| 1 | A | A |
| 2 | B | B |
| 3 | C | C |
| 4 | D | D |
| 5 | E or DD | DD |
| 6 | F or DDD | E |
| 7 | G or DDDD | F |
| 8 | H | FF |
| 9 | I | G |
| 10 | J | GG |
| 11 | K | H |
| 12 | L | HH |
| 13 | M | J |
| 14 | N | JJ |
| Bust/band difference in cm | Continental Europe cup size |
| 10-11 | AA |
| 12-13 | A |
| 14-15 | B |
| 16-17 | C |
| 18-19 | D |
| 20-21 | E |
| 22-23 | F |
| 24-25 | G |
| 26-27 | H |
| 28-29 | I |
| 30-31 | J |
| 32-33 | K |