Small bra size guide: what exists on bands 28 to 32 and in AA to B cups
Small sizes are where retail ranges thin out and old calculators give up. This guide converts the nine sizes at the small end into every system, shows which brand charts actually list them, and explains why a small cup so often comes back "below AA".
Small sizes in every system
| UK | US | EU | FR | AU | JP |
|---|---|---|---|---|---|
| 28AA | 28AA | 60AA | 75AA | 6AA | A60 |
| 28A | 28A | 60A | 75A | 6A | B60 |
| 28B | 28B | 60B | 75B | 6B | C60 |
| 30AA | 30AA | 65AA | 80AA | 8AA | A65 |
| 30A | 30A | 65A | 80A | 8A | B65 |
| 30B | 30B | 65B | 80B | 8B | C65 |
| 32AA | 32AA | 70AA | 85AA | 10AA | A70 |
| 32A | 32A | 70A | 85A | 10A | B70 |
| 32B | 32B | 70B | 85B | 10B | C70 |
"small bra size" gets about 6,600 Google searches a month in the US, 1,600 in the UK and 590 in Australia; "small bra size chart" adds 2,400 in the US (Google Ads cluster figures, September 2026).
From underbust to a small band
Your band is your snug underbust to the nearest even inch. The four smallest bands our calculator uses, and the tape range for each.
| Band (UK / US) | Underbust (in) | Underbust (cm) | EU | AU / NZ |
|---|---|---|---|---|
| 26 | 25 to 26.9 | 64 to 68 | 55 | 4 |
| 28 | 27 to 28.9 | 69 to 73 | 60 | 6 |
| 30 | 29 to 30.9 | 74 to 78 | 65 | 8 |
| 32 | 31 to 32.9 | 79 to 83 | 70 | 10 |
Which charts list them
Nine small sizes against six brands' own printed charts. A chart check, not a stock check.
| Size | Elomi | Freya | Marks & Spencer | Victoria's Secret | The Little Bra Company | ThirdLove |
|---|---|---|---|---|---|---|
| 28AA | Not listed | Not listed | Listed | Not listed | Listed | Not listed |
| 28A | Not listed | Not listed | Listed | Not listed | Listed | Not listed |
| 28B | Not listed | Listed | Listed | Not listed | Listed | Not listed |
| 30AA | Not listed | Not listed | Listed | Listed | Listed | Not listed |
| 30A | Not listed | Not listed | Listed | Listed | Listed | Not listed |
| 30B | Not listed | Listed | Listed | Listed | Listed | Not listed |
| 32AA | Not listed | Not listed | Listed | Listed | Listed | Listed |
| 32A | Not listed | Not listed | Listed | Listed | Listed | Listed |
| 32B | Listed | Listed | Listed | Listed | Listed | Listed |
Smallest band each chart lists: Elomi 32, Freya 28, Marks & Spencer 28, Victoria's Secret 30, The Little Bra Company 28, ThirdLove 32. None of the charts we read lists a 26 band, so the smallest sizes are the ones to check first. The Little Bra Company, a specialist for small sizes, offers AA to D on bands 28 to 38, and its calculator says "We do not currently offer the exact size suggested" when your result is outside that (The Little Bra Company, "Fit Calculator", opened 29 September 2026).
Why small cups come back "below AA"
The traditional +4 method adds 4 inches to an even underbust and 5 to an odd one. A bust within three inches of the band leaves nothing.
| Underbust | Bust | Measured band | +4 method (US) |
|---|---|---|---|
| 26 in | 27 in | 26A | 30 (below AA) |
| 28 in | 29 in | 28A | 32 (below AA) |
| 28 in | 30 in | 28B | 32 (below AA) |
| 30 in | 31 in | 30A | 34 (below AA) |
| 30 in | 32 in | 30B | 34 (below AA) |
| 32 in | 33 in | 32A | 36 (below AA) |
White and Scurr (2012) found the traditional method overestimated band size and underestimated cup size (Ergonomics 55(6)). At the small end the effect is total: every tape above is a real A or B cup, and the padded band has no letter for any of them.
Sister sizes at the small end
Down a band, up a cup keeps the volume. At small sizes the sister often lands on a band nobody lists, so it helps to see the whole diagonal.
| Same volume as | Sisters, tighter band to looser band |
|---|---|
| 28A | 26B, 28A, 30AA |
| 30A | 26C, 28B, 30A, 32AA |
| 32A | 28C, 30B, 32A, 34AA |
Quick answers
What is the smallest bra size?
There is no standard smallest. The charts we read start at a 28 band (Freya, Marks & Spencer, The Little Bra Company), a 30 band (Victoria's Secret) or a 32 band (Elomi, ThirdLove); none lists a 26 band. Our calculator works down to a 26 band (an underbust of about 25 in, 63 cm).
Where can I find an AA cup?
On the charts we read, Marks & Spencer, Victoria's Secret, The Little Bra Company, ThirdLove list an AA. Freya's and Elomi's printed ranges start at B. A chart listing is not stock: check the brand's own size page before you rely on it.
Why does a calculator say I am below AA?
The traditional +4 method pads the band by 4 or 5 inches, so a bust less than four inches above the underbust has no cup letter left. Every tape in the table above is a real A or B cup that the +4 method answers with "below AA". Use the measured-band result instead.
Where to go next
- Bra size calculatorTwo methods side by side, and why they disagree
- How to measureBand, bust and the leaning check, step by step
- Fit checkTick what feels wrong; get the size to try next
- Sister sizesThe whole chart, and what to try when the band rides up
- UK to US converterAny size in any of six systems
- International size chartUK, US, EU, FR, AU and Japan on one grid
- Cup sizes guideWhat a cup letter means, and why it changes by band
- Plus size brasBands 40 and up, cups DD and up: sizing, fit and styles, with the numbers
- Brand size chartsVictoria's Secret, ThirdLove, Wacoal, SKIMS, M&S and Freya, read side by side
- Swimsuit size by bra sizeBra size to bikini top, from brand charts
Sources
Each source was opened and checked on the date shown, or on 25 September 2026. Where sources disagree, the page says so instead of picking one silently.
- The Little Bra Company, "Fit Calculator": its size picker offers bands 28 to 38 and cups AA to D (opened 29 September 2026)
- White J, Scurr J. Evaluation of professional bra fitting criteria for bra selection and fitting in the UK. Ergonomics 2012;55(6):704-711: 45 women; the traditional method overestimated band and underestimated cup
- Victoria's Secret Customer Care, "Size & Fit: International Size Chart (Outside the U.S.)": US sizes sold; bands 30 to 44, cups AA to DDD; US DDD = UK E (opened 26 September 2026)
- Marks & Spencer US, "Bras size guide": UK, AU/NZ, US/CA, EU and FR conversion table (opened 26 September 2026)
- ThirdLove, "Bra Size Calculator & Chart": bands 32 to 44, cups AA to H with half cups; calculator run with 6 measurement pairs (opened 26 September 2026)
- Freya, "International Bra Size Chart & Bra Sizing": band and cup tables in UK, EU, FR, AU/NZ, US and JP (opened 26 September 2026)
- Elomi, "International Size Guide": US underband and cup sizing, B to O cups and 32 to 48 bands; UK, EU, FR, AU/NZ, US and JP rows (UK cups to KK, US to P) (opened 29 September 2026)
- Wikipedia, "Bra size": UK and US cup ladders, the +4 method, EN 13402 and JIS cup steps