Bra Size Chart & Conversion Guide
US, UK, EU and French bra sizes side by side, plus how band and cup are measured and how sister sizes work. Measure with the calculator or convert a known size with the converter.
Bra size conversion chart
Common band and cup combinations across systems. Band numbers map on a fixed scale; cup letters diverge above D, so all systems are shown.
| US | UK | EU | FR |
|---|---|---|---|
| 30A | 30A | 65A | 80A |
| 30B | 30B | 65B | 80B |
| 30C | 30C | 65C | 80C |
| 30D | 30D | 65D | 80D |
| 30DD | 30DD | 65E | 80E |
| 30DDD | 30E | 65F | 80F |
| 30G | 30F | 65G | 80G |
| 32A | 32A | 70A | 85A |
| 32B | 32B | 70B | 85B |
| 32C | 32C | 70C | 85C |
| 32D | 32D | 70D | 85D |
| 32DD | 32DD | 70E | 85E |
| 32DDD | 32E | 70F | 85F |
| 32G | 32F | 70G | 85G |
| 34A | 34A | 75A | 90A |
| 34B | 34B | 75B | 90B |
| 34C | 34C | 75C | 90C |
| 34D | 34D | 75D | 90D |
| 34DD | 34DD | 75E | 90E |
| 34DDD | 34E | 75F | 90F |
| 34G | 34F | 75G | 90G |
| 36A | 36A | 80A | 95A |
| 36B | 36B | 80B | 95B |
| 36C | 36C | 80C | 95C |
| 36D | 36D | 80D | 95D |
| 36DD | 36DD | 80E | 95E |
| 36DDD | 36E | 80F | 95F |
| 36G | 36F | 80G | 95G |
| 38A | 38A | 85A | 100A |
| 38B | 38B | 85B | 100B |
| 38C | 38C | 85C | 100C |
| 38D | 38D | 85D | 100D |
| 38DD | 38DD | 85E | 100E |
| 38DDD | 38E | 85F | 100F |
| 38G | 38F | 85G | 100G |
| 40A | 40A | 90A | 105A |
| 40B | 40B | 90B | 105B |
| 40C | 40C | 90C | 105C |
| 40D | 40D | 90D | 105D |
| 40DD | 40DD | 90E | 105E |
| 40DDD | 40E | 90F | 105F |
| 40G | 40F | 90G | 105G |
How band and cup are measured
Band = snug underbust
Your US/UK band is your ribcage measurement in inches, to the nearest even number. We don't add 4 inches — that old rule makes the band too big.
Cup = bust minus band
The difference between your standing bust measurement and your band, one cup per inch: 1″ = A, 2″ = B, 3″ = C, 4″ = D, and so on.
Sister sizes share cup volume
Going down a band and up a cup keeps the same cup volume (34D = 32DD = 36C). Use them to fine-tune a band that rides up or digs in.
Frequently asked questions
What is a US 34D in UK and EU sizing?
A US 34D is a UK 34D and an EU 75D — the band and cup match at D. Above D the cup letters start to diverge between systems.
Are UK and US bra sizes the same?
Bands match (a 34 band is a 34 band), and cups match up to D. Above D they differ: US uses DD/DDD, the UK uses DD/E/F/FF.
How do French bra sizes work?
French band sizes are the EU band plus 15 — an EU 75 is a French 90. Cup letters follow the EU (straight A–K) scale.
Method & sources
We use the measurement method, not the old +4/+5 rule. The band is your snug underbust measurement in inches (to the nearest even number); the cup is the difference between your standing bust measurement and the band, one cup per inch. US cup lettering above D varies by brand (DD vs E, DDD vs F), so treat letters as a guide and use sister sizes to fine-tune the band while keeping the same cup volume.
Sources: Measurement method per r/ABraThatFits calculator methodology (band = underbust, cup = bust − band); Standard international band scale (US/UK inches → EU/FR), cross-checked retailer charts 2026; Cup-letter divergence US vs UK vs EU documented on major lingerie size charts (2026).