Clothing · Sizing
UK to US bra size converter.
UK and US bands use the same number in inches, so 34 stays 34. The cup letter is where UK sizes go wrong: from DD upward the letters stop matching.
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Same size in every system
Choose a band and cup.
UK to US bra size chart
Examples worked out with the same rules as the converter above (the first column is the system this page starts from).
| UK | US | EU (cm) | FR | AU/NZ | JP (cm) |
|---|---|---|---|---|---|
| 34D | 34D | 75D | 90D | 12D | 75D |
| 34DD | 34DD/E | 75E | 90E | 12DD | 75E |
| 36E | 36DDD/F | 80F | 95F | 14E | 80F |
| 32F | 32G | 70G | 85G | 10F | 70G |
| 34FF | 34H | 75H | 90H | 12FF | 75H |
| 36G | 36I | 80I | 95I | 14G | 80I |
Band sizes
| Underband (in) | UK | US | EU (cm) | FR | AU/NZ | JP (cm) |
|---|---|---|---|---|---|---|
| 28 | 28 | 28 | 60 | 75 | 6 | 60 |
| 30 | 30 | 30 | 65 | 80 | 8 | 65 |
| 32 | 32 | 32 | 70 | 85 | 10 | 70 |
| 34 | 34 | 34 | 75 | 90 | 12 | 75 |
| 36 | 36 | 36 | 80 | 95 | 14 | 80 |
| 38 | 38 | 38 | 85 | 100 | 16 | 85 |
| 40 | 40 | 40 | 90 | 105 | 18 | 90 |
| 42 | 42 | 42 | 95 | 110 | 20 | 95 |
| 44 | 44 | 44 | 100 | 115 | 22 | 100 |
| 46 | 46 | 46 | 105 | 120 | 24 | 105 |
| 48 | 48 | 48 | 110 | 125 | 26 | 110 |
Cup letters, one row per cup volume
Read across a row: every cell is the same cup step in that system. Rows from DD down are where US and UK letters part ways.
| UK | US | EU (cm) | FR | AU/NZ | JP (cm) |
|---|---|---|---|---|---|
| AA | AA | AA | AA | AA | AA |
| A | A | A | A | A | A |
| B | B | B | B | B | B |
| C | C | C | C | C | C |
| D | D | D | D | D | D |
| DD | DD/E | E | E | DD | E |
| E | DDD/F | F | F | E | F |
| F | G | G | G | F | G |
| FF | H | H | H | FF | H |
| G | I | I | I | G | I |
| GG | J | J | J | GG | J |
| H | K | K | K | H | K |
| HH | L | L | L | HH | L |
| J | M | M | M | J | M |
How the conversion works
Band
- US and UK: the underband in inches, even numbers 28 to 48.
- EU: the same underband in centimetres, in steps of 5: EU = 60 + (inches − 28) × 2.5, so 30 = 65, 32 = 70, 34 = 75, 36 = 80.
- Japan and Korea: normally printed as the same centimetre band (65, 70, 75), so the band equals EU.
- France: EU band + 15, so EU 75 is French 90.
- Australia and New Zealand: a dress-size number, US/UK inches − 22, so 30 = 8, 32 = 10, 34 = 12.
Cup
Cups are matched by position on a ladder of cup volumes (AA, A, B, C, D, then upward), not by letter. UK and Australian letters run A, B, C, D, DD, E, F, FF, G, GG, H. US letters run A, B, C, D, DD (also E), DDD (also F), G, H, I, J. EU, French and Japanese letters run one plain letter per step: A, B, C, D, E, F, G, H. So the cup after D is UK DD, US DD/E, EU E, and the cup after that is UK E, US DDD/F, EU F.
The UK FF versus US DDD trap
They are not the same cup. US DDD (also written F) equals UK E. UK FF equals US H. A UK F equals a US G, so US F and UK F are one cup apart. Never copy letters across systems from DD upward.
Limits
- This converts a label to other labels. It does not measure you and cannot guarantee fit: brands cut bands, cups, wires and stretch differently.
- Japanese cups step by 2.5 cm of bust-minus-underband difference against 2 cm in EN 13402 style EU sizing, so the letter conversion for Japan and Korea is approximate.
- Letter conventions above DD vary slightly between brands and countries; some retailers print US F as DDD and others the reverse. Use the label and the retailer's own guide when they disagree.
- If the converted size feels wrong, try a sister size (one band up and one cup down, or one band down and one cup up), which keeps the cup volume close.
Sources
- EN 13402 (size designation of clothes; part 3 covers body measurements and intervals) and ISO 3635 (size designation of clothes, definitions and body measurement procedure): the standards behind the centimetre band and the idea of designating by body measurement. Both are paid documents and were not read for this page.
- The band and cup tables are the arithmetic conventions listed above, written out so you can check them. No retailer or brand size chart is reproduced.
Cite this page: TNAADO Tools, “UK to US Bra Size Converter,” tools.tnaado.ca/calculators/general/bra-size-converter-uk-to-us/, checked October 2, 2026.
Bra size conversion FAQ
What is a UK 34DD in US size?
A UK 34DD is a US 34DD (also written 34E): the band is unchanged and DD matches DD. The change starts one step later: UK 34E is US 34DDD (or 34F).
How do I convert a UK bra size to US?
Keep the band number: UK and US bands are both the underband in inches, so 34 is 34. Then change the cup letter by position, because they differ from DD upward. UK DD = US DD (also written E), UK E = US DDD (also written F), UK F = US G, UK FF = US H, UK G = US I. Cups A to D are the same letter in both.
Is UK FF the same as US DDD?
No. This is the most common mistake. US DDD (also printed as F) is the same cup volume as UK E. UK FF is two sizes bigger and matches US H. UK has no DDD, and a UK F is a US G, not a US F.
What are the EU and French bra sizes for a 34 band?
EU band = centimetres of underband. The ladder runs 60, 65, 70, 75 for US/UK 28, 30, 32, 34, so a 34 is EU 75. French band = EU band + 15, so a 34 is French 90. Cup letters in EU and France run one plain letter per step (A, B, C, D, E, F, G, H) with no double letters.
How do Australian bra sizes work?
The band is a dress-size style number: US/UK band minus 22, so 30 = 8, 32 = 10, 34 = 12, 36 = 14. The cup letters follow the UK scheme (DD, E, F, FF, G). An Australian 12D is a UK 34D and a US 34D.
How are Japanese and Korean bra sizes different?
Both are normally printed as a centimetre band (65, 70, 75) plus a letter, so the band converts the same way as EU. The cup step is where they can differ: Japanese sizing steps cups by 2.5 cm of difference between bust and underband, while EN 13402 style EU sizing steps by 2 cm, so the same letter is not guaranteed to fit the same body. Treat a converted letter as a starting point.
Is a converted bra size a guaranteed fit?
No. This is a conversion of labels, not a fitting. Brands cut bands, cups and wires differently, stretch differs by fabric, and the same size can fit unlike in two styles. If a measured size and a converted size disagree, try both and trust how the bra sits: band level and snug, cups full without gaps or spill, centre gore flat against the breastbone.
Is anything I choose sent or stored?
No. The conversion runs in your browser and nothing is transmitted or saved.
Scope
A label conversion to help you shop across countries. It is not a bra fitting and does not guarantee fit; brands differ. Try on, or check the retailer's own size guide.