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Bra Size Converter

Convert a bra size between US, UK, EU, French and AU systems by list position: US 34C is EU 75C. Shows sister sizes. How it works

Use the Bra Size Converter

Your size
US 34C

Sister Sizes

Sister sizes have the same cup volume but different band/cup combinations. Use these when your exact size is unavailable.

US 36B

36B (sister up: larger band, smaller cup)

US 32D

32D (sister down: smaller band, larger cup)

Equivalent Sizes

SystemBandCupFull Size
US(input)34C34C
UK34C34C
EU75C75C
French90C90C
AU12C12C

Cup letters are not equivalent across systems: each system steps the cup volume by a different amount, so the same letter can mean a different volume. Sizes here match by list position. Check the brand's own chart before you buy.

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About the Bra Size Converter

US 34C is UK 34C, EU 75C, French 90C and AU 12C in this converter. It matches the band and the cup by position in each system’s size list, so the result is an approximation: cup letters are not equivalent across systems, because the systems step cup volume by different amounts.

US sizes in the other four systems

USUKEUFrenchAU
30AA30AA65AA80AA8AA
32B32B70B85B10B
34B34B75B90B12B
34C34C75C90C12C
36C36C80C95C14C
36D36D80D95D14D
38DD38DD85E100E16DD
34DDD/E34E75F90F12E
40F40F90G105G18F
34GG34GGNo equivalentNo equivalent12GG

As the converter’s Equivalent Sizes table shows them, matched by list position. “No equivalent” means that system’s cup list ends before that position.

Band sizes by position in each list

US and UKEUFrenchAU
3065808
32708510
34759012
36809514
388510016
409010518
429511020
4410011522
4610512024

US and UK bands share one list. EU steps by 5, French sits 15 above EU, and AU bands are dress sizes (this tool lists 8 to 24).

How to use this tool

  1. Choose your system, band and cup.
  2. Read the matching size in the other four systems in the Equivalent Sizes table.
  3. Read the sister sizes: one band step up with one cup letter down, and one band step down with one cup letter up.
  4. Compare the result with the brand’s own size chart before you buy.

Frequently asked questions

What is 34C in EU sizes?
75C in this converter. The same position is 90C in French sizes and 12C in AU. Treat it as a starting point, because cup letters differ in volume between systems.
How do I convert a US bra size to EU?
Match the band and the cup by position. US 32, 34, 36 and 38 bands are EU 70, 75, 80 and 85. Cups follow the same order but the lists differ: US 36D is EU 80D, and US 38DD is EU 85E, because the EU list has no DD, FF or GG cups.
What are sister sizes?
Sizes with the same cup volume on a different band. For 34C the sisters are 36B (one band up, one cup down) and 32D (one band down, one cup up). Use them when your size is out of stock.
Is a UK bra size the same as a US size?
Up to DD the two lists are the same here, so US 34DD is UK 34DD. The next US cup is DDD/E and the UK calls the same position E: US 34DDD/E is UK 34E.
Why do US GG and H show “No equivalent” in EU and French sizes?
The EU and French lists in this tool stop at I after ten cups, and the US and UK lists run to twelve, so GG and H have no position to match. US 34GG shows “No equivalent” for both EU and French.
Why is the AU band so different from the US band?
Australian and New Zealand bands are labelled in dress sizes even though they come from an underbust measurement, so US 34 is AU 12 here. French bands are 15 cm above EU bands: EU 75 is French 90.

Reading a size chart from another country

A shop in another country may list bras in a different system: US and UK sizes use inches, EU uses centimeters, French bands sit 15 cm above EU, and Australian bands are dress sizes. Pick a system, band and cup and the table shows the matching size in all five, plus the sister sizes.

This is a lookup between size lists, not a fitting. It has no brand data and measures nothing: to find a size from your underbust and bust measurements, use the Bra Size Calculator under Related Tools. Cup letters are not equivalent across systems, so check the brand's own chart before you buy.

Same position in each list

Each system lists its bands and cups in order, and a size maps to the entry at the same position in every other list. US 34 is the third band, so it maps to EU 75, French 90 and AU 12, and cup C is the fourth cup in every list: US 34C = UK 34C = EU 75C = French 90C = AU 12C.

The lists differ where the systems do. US 38DD maps to EU 85E and AU 16DD, and US 40F to EU 90G, because the EU list has no DD, FF or GG cups. The US and UK lists run to H, but the EU and French lists stop at I after ten cups, so US GG and H show "No equivalent".

Sister sizes move one band step one way and one cup the other: 34C has the sisters 36B (larger band, smaller cup) and 32D (smaller band, larger cup).

US and UK cups step by one letter per inch of difference and other systems by 2 cm, so the same letter can be a different volume.

Fun Fact: Cup letters A to D first appeared in October 1932 from S.H. Camp & Company, and Warner's followed in 1935 with its Alphabet Bra, A to D.

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