Last updated: August 2026
This bra size chart turns two measurements — your underbust and your bust — into your band, your cup, and the equivalent size in the US, UK and EU. Use it alongside the bra size calculator to find and double-check your fit.
How to measure in 20 seconds
- Underbust: snug around the ribcage directly under the bust — this is your band.
- Bust: loose around the fullest part — tape parallel to the floor.
- Subtract: bust minus underbust gives the cup, at about one cup per inch.
Cup size chart (bust − underbust)
Each inch of difference is one cup. Lettering diverges above a D, which is why the same body maps to different letters across regions:
| Bust − underbust | US | UK | EU |
|---|---|---|---|
| 0–1 in (0–3 cm) | AA | AA | AA |
| 1–2 in (3–5 cm) | A | A | A |
| 2–3 in (5–8 cm) | B | B | B |
| 3–4 in (8–10 cm) | C | C | C |
| 4–5 in (10–13 cm) | D | D | D |
| 5–6 in (13–15 cm) | DD | DD | E |
| 6–7 in (15–18 cm) | DDD | E | F |
| 7–8 in (18–20 cm) | G | F | G |
| 8–9 in (20–23 cm) | H | FF | H |
| 9–10 in (23–25 cm) | I | G | I |
| 10–11 in (25–28 cm) | J | GG | J |
Full bra size chart (US)
Find your band down the left, then your bust-minus-underbust difference across the top:
| Band \ diff | 0″ | 1″ | 2″ | 3″ | 4″ | 5″ | 6″ | 7″ |
|---|---|---|---|---|---|---|---|---|
| 28 | 28AA | 28A | 28B | 28C | 28D | 28DD | 28DDD | 28G |
| 30 | 30AA | 30A | 30B | 30C | 30D | 30DD | 30DDD | 30G |
| 32 | 32AA | 32A | 32B | 32C | 32D | 32DD | 32DDD | 32G |
| 34 | 34AA | 34A | 34B | 34C | 34D | 34DD | 34DDD | 34G |
| 36 | 36AA | 36A | 36B | 36C | 36D | 36DD | 36DDD | 36G |
| 38 | 38AA | 38A | 38B | 38C | 38D | 38DD | 38DDD | 38G |
| 40 | 40AA | 40A | 40B | 40C | 40D | 40DD | 40DDD | 40G |
| 42 | 42AA | 42A | 42B | 42C | 42D | 42DD | 42DDD | 42G |
| 44 | 44AA | 44A | 44B | 44C | 44D | 44DD | 44DDD | 44G |
Band size conversions
| US | UK | EU | FR | AU |
|---|---|---|---|---|
| 28 | 28 | 60 | 75 | 6 |
| 30 | 30 | 65 | 80 | 8 |
| 32 | 32 | 70 | 85 | 10 |
| 34 | 34 | 75 | 90 | 12 |
| 36 | 36 | 80 | 95 | 14 |
| 38 | 38 | 85 | 100 | 16 |
| 40 | 40 | 90 | 105 | 18 |
| 42 | 42 | 95 | 110 | 20 |
| 44 | 44 | 100 | 115 | 22 |
Cup letters convert too: a US DD is a UK DD but an EU E; a US DDD is a UK E and an EU F. When a brand lists a single country’s sizing, convert the band and the cup together.
How to check the fit is actually right
Numbers get you to the right size on paper; these hands-on checks tell you whether it fits in real life. Do them in front of a mirror, wearing the bra on the loosest hook:
- Band: it should sit level all the way around, in line with the front. Slide two fingers under it at the back — snug, not loose, no riding up when you raise your arms. The band does roughly 80% of the support work, so this matters most.
- Cups: do a quick “scoop and swoop” — lean forward, settle everything into the cup, then stand up. There should be no spillage over the top or sides, and no wrinkling or gaping at the edge. Spillage means size up a cup; gaping means size down a cup.
- Centre gore: the little bridge between the cups should lie flat against your breastbone. If it floats off the body, the cup is usually too small.
- Straps: you should fit a finger under them comfortably. If they dig in or carry most of the weight, the band is too loose — tighten it or size the band down.