Bra size converter & calculator
Enter your measurements to find your size, or convert a size you already know across every system. The calculator handles the tricky cup-letter differences above a D cup. US, UK, EU, France, Italy, Japan and Australia all covered.
Your size (US)34CC cup
Sizes are the standard retail conversions. Cup letters above D differ between systems — this tool handles that. Brands still vary, so treat the result as your starting size.
How to measure your bra size
You need two measurements, taken with a soft tape. Measure braless or in a thin non-padded bra for the truest result.
1. Band (underbust). Wrap the tape snugly around your ribcage, directly under your bust, parallel to the floor. Exhale and read the number. Round to the nearest even number — that's your band size.
2. Bust. Measure around the fullest part of your bust, tape level and not pulled tight.
3. Cup. Subtract the band from the bust. Each inch of difference is one cup: 1″ = A, 2″ = B, 3″ = C, 4″ = D, 5″ = DD, and up. The calculator above does this for you.
Two band methods exist. The modern method (used here) takes your underbust rounded to the nearest even number. An older US method added 4–5 inches to the underbust — it tends to give a band that's too loose and a cup that's too small, which is why so many people are mis-sized. If your current bra band rides up at the back, your band is probably too big.
Band size conversion chart
The band number means different things in different countries: US and UK use inches, the EU and Japan use centimetres, France and Spain add 15 to the EU number, Italy uses a short scale, and Australia/NZ use dress-style numbers.
| US / UK (in) | EU / JP (cm) | FR / ES | IT | AU / NZ |
|---|---|---|---|---|
| 28 | 60 | 75 | — | 6 |
| 30 | 65 | 80 | 0 | 8 |
| 32 | 70 | 85 | 1 | 10 |
| 34 | 75 | 90 | 2 | 12 |
| 36 | 80 | 95 | 3 | 14 |
| 38 | 85 | 100 | 4 | 16 |
| 40 | 90 | 105 | 5 | 18 |
| 42 | 95 | 110 | 6 | 20 |
| 44 | 100 | 115 | 7 | 22 |
Cup size conversion chart
Through the D cup every system agrees. Above D they diverge — this is where almost all sizing mistakes happen. A US 34G is a UK 34F and an EU 75G: same body, three labels.
| Bust − band | US | UK | EU / FR / IT / JP |
|---|---|---|---|
| 1" | A | A | A |
| 2" | B | B | B |
| 3" | C | C | C |
| 4" | D | D | D |
| 5" | DD | DD | E |
| 6" | DDD / F | E | F |
| 7" | G | F | G |
| 8" | H | FF | H |
| 9" | I | G | I |
| 10" | J | GG | J |
US cup letters vary by brand above DD — some use DDD/F/G, others jump to E/F. UK uses the DD, E, F, FF, G, GG ladder. EU (and France, Italy, Japan) use single continuous letters where EU E equals US DD. When in doubt, size the cup up: you can shorten a band, but you can't add cup volume.
Sister sizes
If your exact size isn't in stock, a sister size gives the same cup volume with a different band. Go down a band and up a cup, or up a band and down a cup. For example, 34C ↔ 32D ↔ 36B all share the same cup volume.
| Your size | Smaller band | Larger band |
|---|---|---|
| 34B | 32C | 36A |
| 34C | 32D | 36B |
| 34D | 32DD | 36C |
| 36C | 34D | 38B |
| 32D | 30DD | 34C |
Frequently asked questions
How do I measure my bra size at home?
Measure your underbust snugly and round to the nearest even number for the band. Measure the fullest part of your bust, then subtract the band from the bust — each inch of difference is one cup size (1″ = A, 2″ = B, 3″ = C, and so on). The calculator on this page does the maths for you.
What is 80B in US bra size?
An 80 band in EU/cm sizing equals a US 36 band, and the B cup is the same, so 80B converts to US 36B.
Is a US DD the same as a EU E?
Yes. A US DD cup is equal to a EU E cup. The systems match through D, then the EU uses single continuous letters (E, F, G) while the US uses DD, DDD and beyond.
What is the difference between US and UK cup sizes?
Band numbers and cups match through DD. Above that they split: a US DDD/F is a UK E, a US G is a UK F, and a US H is a UK FF. Always check the cup column when shopping across systems.
Why do bra sizes feel different between brands?
There is no single international standard, so a 34C can fit differently between makers because of cut, fabric stretch and fit model. Use the conversion as a starting size and check each brand's own chart and reviews.
What are sister sizes?
Sister sizes share the same cup volume with a different band. Going down a band and up a cup (34C to 32D) or up a band and down a cup (34C to 36B) keeps the cup volume the same — useful when your exact size is out of stock.