US Bra Size to UK Conversion Guide
Bridge the gap between American and British bra sizing with clear cup translations, real-world examples, and fit tips you can trust.
Covers cup sizes AA through P and band sizes 26-52.
Band numbers stay the same
A US 34 band equals a UK 34. Focus on changing the cup letter unless you intentionally tighten or loosen the band.
Double letters signal half steps
The UK scale inserts FF, GG, and HH instead of jumping straight to G, H, or I. Slide one letter back when converting from most US labels.
Check the brand origin first
UK heritage brands already print UK sizes even on US hang tags. US-born brands usually need the conversion chart below.
US-to-UK Cup Letter Conversion
Match the cup you wear in US sizing to the letter you'll see on UK bras. Band numbers remain the same.
| US Label | UK Equivalent | Notes |
|---|---|---|
AA | AA | Identical labeling in both systems. |
A | A | Direct match. |
B | B | Direct match. |
C | C | Direct match. |
D | D | No change required. |
DD Sometimes listed as E in US stores | DD | UK keeps the double letter to show the half step after D. |
DDD / F Often shown as F on US size charts | E | Drop the extra D. UK prints a single E at this volume. |
G | F | UK adds FF between F and G, so shift one letter back. |
H | FF | Add the second F to match the UK scale. |
I | G | Move back one letter for the UK equivalent. |
J | GG | Double the letter after G on UK charts. |
K | H | Return to the single H in the UK progression. |
L | HH | Double the H to align with UK sizing. |
M | J | UK jumps to J at this volume. |
N | JJ | Add the extra J for the UK label. |
O | K | Shift one letter back to K. |
P | KK | Specialty full-bust brands use KK for this range. |
How to Convert Your Size Step-by-Step
- Confirm your current US size Measure your snug underbust and full bust or start from a bra that fits well to ensure your baseline is accurate.
- Match the cup using the chart Keep the same band number and swap the cup letter to the UK equivalent. For example, 36DDD becomes 36E.
- Check sister sizes if needed If the converted size feels tight or loose, move one band size up or down and adjust the cup the opposite direction.
- Verify with a try-on Every brand fits a little differently. Try nearby sizes or read fit reviews to confirm before removing tags.
Worked Conversion Examples
US 34DDD (F) -> UK 34E
Triple letters in US labeling collapse to a single letter in the UK scale.
US 32G -> UK 32F
Because UK adds FF after F, the US G shifts back one letter.
US 30H -> UK 30FF
Add the second letter to align with the British sequence.
US 38I -> UK 38G
Bands stay identical. Only the cup letter changes.
Brand Sizing Cheat Sheet
Use this to decide whether you need to convert the label or trust what you see.
US-focused retailers
- Victoria's Secret
- ThirdLove
- Lane Bryant
- Soma
Labels usually follow the US alphabet. Convert to UK before ordering British imports from these stores.
UK heritage brands
- Panache
- Freya
- Curvy Kate
- Bravissimo
Products ship with UK sizing by default. Any US letters on the tag are secondary references.
Global sports bras
- Shock Absorber
- Nike
- Adidas
High-impact models tend to use UK cups. Check product descriptions for the sizing system before converting.
Fit Tips After Converting
- If a hang tag shows multiple columns (UK/EU/FR), rely on the UK column even in US stores.
- Look for size listings like 34DDD / 34F / 34E. Manufacturers often print the UK equivalent right beside the US code.
- When shopping online, filter reviews by cup size to confirm whether the conversion people ordered runs small or full.
Helpful Tools
Interactive Bra Size Calculator
Measure in inches or centimeters and generate US, UK, and EU sizes before you shop.
OpenInternational Bra Size Guide
Compare US, UK, EU, FR, IT, JP, and AU systems in one place with conversion tips.
OpenSister Bra Size Chart
Explore alternate band-and-cup pairs to fine-tune your converted size.
OpenUS to UK Conversion FAQ
Why do UK bra cups use double letters after D?
British sizing keeps every half-step in the alphabet, so DD, FF, GG, and HH all exist. US charts collapse some of those steps into single letters like G or H, which is why you slide one letter back when converting.
How can I tell if a bra already follows UK sizing?
Check the brand's origin and look for extra columns on the size label. If the tag highlights UK or UK/USA sizing separately, trust the UK column. Brands manufactured in the UK almost always use the British scale worldwide.
Does converting the cup change the band fit?
No. Band numbers represent the same body measurement in inches across US and UK systems. Only adjust the band when you intentionally want a tighter or looser fit, then offset with the appropriate sister size cup.
What if my converted UK size is hard to find in stock?
Search retailers that specialize in UK full-bust brands, or try the nearest sister size. For example, if 34FF is unavailable, test 32G or 36F to preserve cup volume.