Australian bra sizes look different from UK or US sizes: the band is a small number such as 12 and not 34, and the measurements are taken in centimetres. The system is simple once you know it. Your underbust gives the band in steps of 5 cm, and the difference between bust and band gives the cup. This calculator does both steps for you and shows the matching UK, US and European sizes.
How to use the Australian bra size calculator
- Measure your underbust: tape directly under the bust, on bare skin if you can, straight and firm, breathing out.
- Measure your overbust: in a non-padded or lightly padded bra, tape around the fullest part, level and not tight. Repeat to check you get the same figure.
- Enter both in centimetres or inches.
- Read your size. The cup is taken from your overbust relative to the centre of your band.
Australian bra size formula
cup = (overbust − (65 + 5k)) in 2 cm steps: A = 12 to under 14, B = 14 to under 16, C, D, DD, E, F, G, H = 28 to under 30
UK / US band = AU band + 22 · EU band = 65 + 5k
The ranges are copied from Berlei’s size guide as shown by Rebel Sport (retrieved 2026-10-15) and agree with the worked example in Myer’s bra fitting guide. Berlei prints each cup range with a shared edge (such as C 91–93 and D 93–95); the calculator gives the larger cup at an edge, following Myer’s example of a 93 cm overbust in a 12D.
| AU band | Underbust (cm) | EU band | UK/US band | A (cm) | B (cm) | C (cm) | D (cm) |
|---|---|---|---|---|---|---|---|
| 8 | 63–67 | 65 | 30 | 77–79 | 79–81 | 81–83 | 83–85 |
| 10 | 68–72 | 70 | 32 | 82–84 | 84–86 | 86–88 | 88–90 |
| 12 | 73–77 | 75 | 34 | 87–89 | 89–91 | 91–93 | 93–95 |
| 14 | 78–82 | 80 | 36 | 92–94 | 94–96 | 96–98 | 98–100 |
| 16 | 83–87 | 85 | 38 | 97–99 | 99–101 | 101–103 | 103–105 |
| 18 | 88–92 | 90 | 40 | 102–104 | 104–106 | 106–108 | 108–110 |
| 20 | 93–97 | 95 | 42 | 107–109 | 109–111 | 111–113 | 113–115 |
| 22 | 98–102 | 100 | 44 | 112–114 | 114–116 | 116–118 | 118–120 |
| 24 | 103–107 | 105 | 46 | 117–119 | 119–121 | 121–123 | 123–125 |
| 26 | 108–112 | 110 | 48 | 122–124 | 124–126 | 126–128 | 128–130 |
Cups continue with DD (20–22 cm above the band centre), E (22–24), F (24–26), G (26–28) and H (28–30). Berlei prints the larger cups only for bands 10 to 26.
Worked example
Underbust 76 cm, overbust 93 cm.
- 76 cm falls in the 73–77 cm range → band 12, centre 75 cm.
- Difference: 93 − 75 = 18 cm, which is the lower edge of the D range → cup D.
- Australian size 12D; UK and US 34D / 34D; European 75D.
Getting a good fit
- Check the band first: it should be level and snug, and does most of the support.
- Cup test: the breast should fill the cup with no gaps and no spill.
- Try neighbours: a size either side can fit better because brands differ.
- Re-measure: bodies change, and a size from a few years ago may no longer be right.
For other countries use the Bra Size Converter (US/UK/EU/AU/FR/JP), and for the UK system the UK Bra Size Calculator. This page gives general sizing information and is not a professional fitting.
Sources
Every figure above comes from these pages, read directly on the dates shown. Brand names are used only to identify published charts.
- Berlei (Rebel Sport) — size guide: underbust and overbust in centimetres — checked 2026-10-15
- Myer — bra fitting guide (Australian bra size chart and worked example) — checked 2026-10-15
- Wikipedia — Brassiere measurement (Australian cup scale) — checked 2026-10-15
Frequently asked questions
How do I find my Australian bra size?
Measure your underbust snugly in centimetres to get the band: 63–67 cm is a size 8, 68–72 a 10, 73–77 a 12 and so on in steps of 5 cm. Then measure your overbust and read the cup from the column for your band. Myer’s example is a 76 cm underbust and 93 cm overbust, a 12D.
How does an Australian size convert to UK or US?
The Australian band is 22 lower than the UK or US band: AU 12 is 34. The cup letters match through D, then Australian sizes run DD, E, F, G, H without the doubled letters used in UK sizing.
Are Australian cups the same as UK cups?
Up to DD, yes. After that Berlei’s chart and the Wikipedia scale have DD, E, F, G, H, where UK sizing has E, F, FF, G, GG. Brava’s converter and Fantasie’s chart treat them as equal, so brands differ; the calculator shows the UK size beside the Australian one.
Why is my cup on the line between two letters?
Berlei prints ranges that share their edge, for example C 91–93 and D 93–95. Myer’s worked example puts 93 cm in the D cup, so this calculator gives the larger cup at an edge. Try both and see the Sister Size Calculator.
Do New Zealand sizes match?
Yes, New Zealand uses the same bands and cups as Australia. See also Bra Size Converter (US/UK/EU/AU/FR/JP) for other countries.