Bra Size Calculator

Follow these easy steps to estimate your Australian Bra Size to help you choose the right bra.

Step 1:

While wearing a bra, measure around your body, under your bust in inches.

Position the tape measure over the band of your bra and adjust it so it fits comfortably around your body.


Use the grid below to convert this measurement to your Australian bra band size.

(Keep this measurement handy as you will also need it in Step 2)

Step 2:

Measure over the fullest part of your bust.

The tape measure should sit snug, but not too firm.


To estimate your cup size, you will need to subtract the underbust measurement from step 1 from the over bust measurement.

Step 2 measurement – Step 1 measurement = Cup Size


The difference between these two measurements will enable you to work out your cup size, using the below grid. You will find each inch of difference will equate to one cup size.


Step 1 measurement: 34″
As from the grid in step 1, we can conclude the band is a size 12.
Step 2 measurement: 39″
Step 2 measurement – Step 1 measurement = Cup Size
39″- 34″ = 5″
Using the cup size grid, we can conclude the cup size to be a DD.
Therefore the Australian Bra Size is 12DD.




  • If your underbust measurement at Step 1 is an odd number, as a general guide, you can round the number down if you prefer your bra to fit firmly, or round up if you prefer a more relaxed fit.


  • This calculator is to be used as guide only. The measurements will vary depending on the bra you are currently wearing. If you are wearing a bra that compresses the bust, eg a minimiser bra or a bra that is too small, you may need to adjust the overbust measurement accordingly.


  • Different brands and styles of bras fit differently. For example, it is not uncommon to be a 12DD in one particular bra, but need a 12E in another bra style or brand.


  • Cup sizes are not universal across different back/band sizes. For example, a 10E cup is not the same size as a 14E cup. The size of an E cup underwire and capacity changes depending on the band size.


  • We highly recommend coming in to our store and getting fitted by our trained and professional Fitting Specialists. We will take the hard work out of bra shopping and will find the perfect bra for you. We realise this is not always possible however, especially if you live outside the Perth metro area, so please contact us on 08 92271950 if you need assistance in finding a bra to suit your figure.