Lifestyle & Utility
Bra Size Calculator
Calculate your Australian bra size from under-bust and over-bust measurements, with sister sizes.
How this calculator works
Rounds the under-bust measurement to the nearest even number for the band size. Calculates the difference between over-bust and under-bust measurements — each 2cm difference equals one cup size (A=10cm, B=12cm, C=14cm, D=16cm, DD=18cm, E=20cm, F=22cm). Also generates sister sizes one band up and down.
Measure snugly around your ribcage directly under your bust
Measure around the fullest part of your bust without compressing
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FAQ
Frequently asked questions
How do I measure for a bra correctly?
Use a soft tape measure. Under-bust: measure around your ribcage directly under your bust, keeping the tape snug but not tight. Over-bust: measure around the fullest part of your bust, keeping the tape level and not compressing. Measure while wearing a non-padded bra.
What are sister sizes?
Sister sizes have the same cup volume but different band sizes. If a 12C is slightly tight in the band, try a 14B (same cup volume, larger band). If it is loose, try a 10D (same cup volume, smaller band).
What is the most common bra size in Australia?
The most commonly sold bra size in Australia is reportedly 14C-D. However, research suggests many women wear the wrong size — studies indicate up to 80% of women may be wearing an incorrect bra size.
How do AU bra sizes compare to US?
AU band sizes are 16 numbers larger than US (AU 12 = US 34). Cup letters are generally the same (AU C = US C). So AU 12C = US 34C. UK sizing is similar to AU for cups but uses different band numbers.
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