Bra Size Converter
Convert US bra sizes to UK and EU equivalents. Enter US band size and cup letter.
How to use this tool
- Enter us band size and cup size in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your uk size and the full breakdown beneath it.
Convert your US bra size to UK and EU equivalents quickly and accurately.
Formula
UK Size = US Band + Cup Letter (unchanged)
EU Band = US Band × metric equivalent (32→70, 34→75, 36→80, 38→85, 40→90)
EU Cup = Cup Letter (DD becomes E in EU notation)
How it works
US and UK bra sizing share the same band-and-cup letter system, so the UK size is simply the US band number followed by the cup letter. The EU system shifts to centimetre-based bands measured in increments of 5 cm, starting from 70 cm (≈ US 32), while cup letters remain the same with the exception that DD is written as E. A common mistake is assuming EU cup letters map one-for-one with US cups across all sizes — they do for most letters, but DD/E and any double letters beyond that diverge between markets, so always verify the specific cup mapping when converting above a D cup.
Worked example
Converting US 34B to UK and EU sizes
- Start with US band 34 and cup B.
- UK size: band and cup carry over directly → 34B.
- EU band: look up 34 in the band table → 75.
- EU cup: B has no special mapping, so it stays B → EU size is 75B.
UK Size: 34B | EU Size: 75B
Common mistakes to avoid
- Assuming the cup letter means the same cup volume across band sizes -- a 34D and a 38D have very different cup volumes; cup volume increases with band size (sister sizing).
- Forgetting that EU cup notation differs -- what US/UK calls DD, EU often calls E; cup letters can diverge further at larger sizes (US DDD = EU F in some brands).
- Measuring bust circumference alone without also measuring the underbust -- band size comes from the underbust measurement, not the bust; using bust measurement only produces an incorrectly large band size.
Key terms
- Band size
- The number in a bra size, representing the circumference of the ribcage measured in inches (US/UK) or centimetres (EU) just below the bust.
- Cup size
- The letter in a bra size, representing the difference between the bust measurement and the band measurement; each letter corresponds to roughly one inch or 2.5 cm of difference.
- EU band increment
- EU band sizes increase in steps of 5 cm, mapping roughly as: US 32 = EU 70, US 34 = EU 75, US 36 = EU 80, and so on.
- DD vs E
- In EU sizing, the cup that US and UK markets label DD is written as E; cup letters beyond D diverge further between regional sizing systems.
Frequently asked questions
- Is a US 34B the same as a UK 34B?
- Yes — for band sizes 32–40 and cups A through D, US and UK bra sizes use the same notation. The EU system uses a different band number (EU band = US band + 16 in cm, e.g. US 34 = EU 75).