What bra size conversion actually does
Every bra size has two pieces of information: how long the band is, and how much the cup holds relative to that band. Every country writes those two facts in its own way. Converting a size is only a change of language. The bra you would get in the new system is the same bra.
The converter above does the arithmetic for bands and looks up the cup letters for you. Choose the country on the tag, enter the size, and choose the country you are shopping in.
How bands convert
Bands follow simple rules, so you can check the converter in your head:
- US and UK share the same inch numbers: 32, 34, 36.
- Australia and New Zealand subtract 22. A 34 becomes AU 12.
- EU uses centimeters in 5 cm steps. A 32 band is EU 70 and a 34 is EU 75.
- France, Belgium and Spain add 15 to the EU figure. EU 75 is FR 90.
Australian band numbers borrow the dress-size scale, which is why many Australian shoppers find them familiar. They are still a band size, so convert them rather than guessing from a dress label.
How cups convert
Up to DD, US, UK and AU cup letters are the same. Above DD the systems split:
- The UK runs DD, E, F, FF, G, GG.
- The US often runs DD, DDD, then G and H. So a UK E is a US DDD, a UK F is a US G, and a UK FF is a US H.
- EU and FR use plain single letters. A UK DD is an EU E, and a UK E is an EU F.
- AU usually follows UK letters, though some local brands drop the double letters above DD.
US letters above DDD are not consistent between brands. Some use DDDD, some use F, some jump to G. The converter uses the most common pattern. Check the brand’s own chart before you order.
Worked conversions
A few examples to show the pattern:
- US 36DDD = UK 36E = AU 14E = EU 80F = FR 95F.
- UK 32FF = US 32H = EU 70H.
- EU 70E = US 32DD = UK 32DD = AU 10DD.
Notice that the band always follows its rule, while the cup letter moves only above DD.
When a conversion is not enough
A conversion is exact on paper. A bra can still fit differently across brands, because elastic tension, wire shape and cup depth are not standardized. Some brands run small in the band, some run large in the cup.
If a converted size feels slightly off, try a sister size before you change system again. Going down one band and up one cup, or the reverse, keeps the cup volume and changes only the band.
If you do not know the starting size at all, conversion cannot help yet. Measure first with the how to measure bra size guide, or read the tag on a bra that already fits.
Country pages
For the most common pairs, there is a page with its own notes:
- UK to US bra size
- US to UK bra size
- Australian bra size conversion
- EU and international bra size conversion
The full bra size chart shows every band and cup at once.
Sources & method: sizing rules follow the standard band-and-cup system used by UK, US, AU and EU brands, checked against fitting guides from specialist retailers and fitting communities. How we work.