🩱 Bra Size Converter
A US 34DD is a UK 34DD but an EU 75E and a FR 90E — band systems translate cleanly, cup letters diverge past D. Convert below — everything happens on your device.
US
34D
UK
34D
EU / DE
75D
FR / ES
90D
AU (band)
12D
Sister sizes (same cup volume):
Your measurements never leave this page — nothing is transmitted or stored.
How to measure
- Band: measure snugly around the ribcage, directly under the bust, in inches or cm — exhale first; the tape should be level and firm.
- Bust: measure around the fullest point, unpadded, tape parallel to the floor.
- Cup = bust minus band: each inch (2.5 cm) of difference is one cup step (1" ≈ A, 2" ≈ B, 3" ≈ C…).
- Enter your current size in the converter to see every system plus your sister sizes.
Sister sizes share the same cup volume on a different band: 34DD, 36D and 32DDD hold the same — the letter changes because cup letters are relative to the band. If a band rides up, go down a band and up a cup; if it digs in, the reverse. Roughly 8 in 10 people measure into a different size than they habitually buy, which is why the sister-size feature exists.
Band size conversion chart
| US / UK | EU / DE | FR / ES | IT | AU |
|---|---|---|---|---|
| 28 | 60 | 75 | 0 | 6 |
| 30 | 65 | 80 | 1 | 8 |
| 32 | 70 | 85 | 2 | 10 |
| 34 | 75 | 90 | 3 | 12 |
| 36 | 80 | 95 | 4 | 14 |
| 38 | 85 | 100 | 5 | 16 |
| 40 | 90 | 105 | 6 | 18 |
| 42 | 95 | 110 | 7 | 20 |
| 44 | 100 | 115 | 8 | 22 |
Cup ladder comparison
| Cup step | US | UK | EU |
|---|---|---|---|
| 1 | A | A | A |
| 2 | B | B | B |
| 3 | C | C | C |
| 4 | D | D | D |
| 5 | DD | DD | E |
| 6 | DDD | E | F |
| 7 | G | F | G |
| 8 | H | FF | H |
| 9 | I | G | I |
| 10 | J | GG | J |
Frequently asked questions
What is a sister size?
The same cup volume on a different band length. One band size down + one cup letter up (or the reverse) keeps volume constant: 34DD ↔ 32DDD ↔ 36D. Useful when a style fits in the cup but not the band.
What is a US 34DD in EU sizing?
75E. The band converts 34→75 (inches to the EU cm scale), and the fifth cup is DD in the US ladder but E in the EU ladder.
Why do UK and US cups differ above D?
The ladders fork: US goes D, DD, DDD, G…; UK goes D, DD, E, F, FF, G…. A UK F is roughly a US DDD/G — always convert by counting cup steps, not matching letters.
Is my measurement data stored anywhere?
No. Like every LazyTools tool, the converter runs entirely in your browser — body measurements are never transmitted, logged or stored. You can verify with your browser’s network tab.
Is this bra size converter private?
Yes — it runs entirely in your browser. Sizes and body measurements are never sent to a server, logged or stored, and the page works offline.