How to Read a Bra Size Chart: UK vs US vs EU Conversion
A bra size chart converts the same body between US, UK, EU, French and Japanese labels. Learn how bands and cup letters map across systems — and where the systems quietly disagree.
Usage Guide
Sizing Reference
If you have ever bought a "75E" on holiday and found it nothing like your usual "34DDD," the chart was not lying — you were reading two systems that describe the same body with different labels. Convert the band and the cup as two separate steps and the mystery disappears. Below is exactly how each system is built, where they line up, and the one place they quietly disagree.
A bra size is two measurements, not one
Every system starts from the same two numbers: the underbust (the firm circumference directly below the bust, which sets the band) and the bust (around the fullest part, which sets the cup). The cup letter encodes only the difference between bust and band — roughly one inch, or about 2.5 cm, per letter — which is why the cup letter alone is meaningless without its band. That is also the basis of sister sizes and of cup size versus cup volume: the same letter on a wider band holds more. To turn your tape measurements into a starting size in either inches or centimetres, run them through the bra size calculator first, then convert the result with the tables here.
Bands: US and UK agree, the EU counts in centimetres
The band is the easy half. The US and UK use the same band numbers in inches (32, 34, 36…), so no conversion is needed between them. The EU labels the band in a centimetre-derived retail number — a US/UK 34 band is commonly written EU 75, a 36 is EU 80, a 38 is EU 85, stepping by 5 for every 2 inches. France (and Spain) take the EU step and add 15, so a US 34 becomes France 90. These offsets are the convention published across major brand and retailer conversion charts (Cloth Habit bra size conversion chart, accessed 2026-06-23).
| US / UK band (in) | EU band | France band |
|---|---|---|
| 30 | EU 65 | FR 80 |
| 32 | EU 70 | FR 85 |
| 34 | EU 75 | FR 90 |
| 36 | EU 80 | FR 95 |
| 38 | EU 85 | FR 100 |
| 40 | EU 90 | FR 105 |
Cups: identical through D, then they split
Cup letters are where charts earn their keep. Through a D cup, the US, UK and EU letters line up, so an A/B/C/D is an A/B/C/D almost everywhere. Above D the sequences diverge: the US repeats letters (D, DD, DDD, and only then single letters), while the UK runs D, DD, E, F, FF, G, GG with no "DDD." The EU follows the UK-style single-letter run. The practical result, as set out across international converters, is that a US DD is usually an EU E, a US DDD/F is a UK E and EU F, and a US G is a UK F (Olivia Paisley international cup-size guide, accessed 2026-06-23). This is also why how bra sizing works looks inconsistent at a glance — the letters are a sequence, not a fixed measure.
| US cup | UK cup | EU cup |
|---|---|---|
| D | D | D |
| DD | DD | E |
| DDD / F | E | F |
| G | F | G |
| H | FF | H |
Japan and the wider world: the band counts the same, the cup steps differently
Outside Europe the band logic is similar but the cup step can change. Japanese (JIS) sizing labels the band in centimetres much like the EU, but cup steps are defined by the top-bust minus under-bust difference in centimetres, so a body that reads US 34DD often lands around a Japanese 75F. Worked examples in cross-region converters put a US 34DD → UK 34E → EU 75E/F → Japan 75F (sometimes G) (HauteFlair US/UK/EU/JP conversion, accessed 2026-06-23). The lesson is not to memorise every country — it is to always convert band and cup as two separate steps, then verify on the body.
Where conversion charts stop helping
A chart translates the label, never the cut. Bra sizing is not standardized the way screw threads are; two makers can both print "75E" and fit a full band size apart, and even the international standard for clothing labels, ISO 3635 (now superseded by ISO 8559-1), defines the body-measurement procedure rather than a binding cup grade. So use the conversion to get into the right band-and-cup neighbourhood, then do the fit work: try the size and one sister size on the loosest hook, level, snug enough for two fingers under the band. If you are sizing smoothing or shaping layers rather than a bra, size those from your body measurements instead of your bra label — brands that publish honest body-measurement charts, like Shapeshe, make that step easier.
Frequently asked questions
Is a US 34C the same as a UK 34C?
Through a D cup the US and UK systems line up closely, so a US 34C is usually a UK 34C. They only diverge above D: the US repeats letters (DD, DDD) while the UK runs DD, E, F, FF, G — so a US 34DDD is commonly written 34E in the UK for the same body.
How do I convert my US band to an EU band?
EU bands are centimetre-based labels: a US/UK band number maps to roughly that band plus about 41 — a US 34 is EU 75, a 36 is EU 80, a 38 is EU 85. France adds 15 to the EU number, so a US 34 becomes France 90.
Why does my converted size still not fit?
A chart converts the label, not the cut. Bra sizing is not standardized across brands or countries, so a converted 75E can still run small or large by maker. Convert to get the right neighbourhood, then try the size and its sister sizes on the loosest hook.
Which number is the band and which is the cup?
The number is the band (underbust circumference) and the letter is the cup (the bust-minus-band difference, about one inch or 2.5 cm per letter). Convert the two separately — the band by a country offset, the cup by a country letter sequence.
Shape Finder is a free educational tool. We sell nothing and store no measurements — the math is shown so you can check it. Conversion figures are the common conventions published across brand and retailer charts; because bra sizing is not standardized, treat any converted size as a starting point and confirm fit on the body.