Last updated: July 27, 2026
A US 34C, a UK 34C, and an EU 75C can all describe the exact same bra. So can a US 34DD and a UK 34E, which look like two different sizes on a label but fit identically. If you have ever ordered a European brand true to your usual size and had the band feel loose, or picked a UK size and found the cup ran high, this is why. Every country built its own bra sizing convention, mostly in isolation, and none of them ever synced up into one global standard. This guide breaks down exactly how US, UK, EU, and other international sizes convert, so you can read any brand's chart with real numbers instead of guesswork.
Every piece in our bra collection is built to a specific band and cup measurement, which matters just as much whether you found us through a US, UK, or EU-labeled search.
Key takeaways
- US and UK bra sizes are identical, band and cup, up through a D cup. They only diverge above that.
- EU and French sizes measure the band in centimeters instead of inches, so a US 34 becomes an EU 75.
- Past a D cup, EU and French cup letters shift by one full letter compared to US: EU E equals US DD, EU F equals US DDD.
- Australia and New Zealand use the same system as the UK. Italy and Japan generally follow the EU centimeter-based band, though the exact labeling varies by brand.
- There is no single worldwide bra sizing standard, so the same measurements can produce three or four different-looking size labels depending on where the brand is from.
Why bra sizes aren't the same from country to country
Bra sizes differ by country for two reasons: band measurements are recorded in different units (inches in the US and UK, centimeters through most of Europe and Asia), and cup letters were never standardized internationally once they extend past a D cup. Two people with identical measurements can end up needing a US 34C, a UK 34C, and an EU 75C label for the same garment. All three describe one fit.
US to UK bra size conversion
US and UK bra sizes match exactly through a D cup, both the band number and the cup letter. A US 34C is a UK 34C, no conversion required. The two systems only split once you pass D: US brands typically continue with DD and DDD, while UK brands move to DD, then E, F, FF, and G.
US to EU and French bra size conversion chart
To convert a US or UK size to EU or French sizing, translate the band from inches into a centimeter-based number in five-centimeter steps, then shift the cup letter by one once you're past a D.
| US / UK band | EU / FR band |
|---|---|
| 30 | 65 |
| 32 | 70 |
| 34 | 75 |
| 36 | 80 |
| 38 | 85 |
| 40 | 90 |
| 42 | 95 |
| 44 | 100 |
Cup letters match exactly through D: a US 34C is an EU 75C. Past that point, they shift: EU E equals US DD, and EU F equals US DDD. Beyond that, labeling varies enough by brand that it is worth checking the specific chart rather than assuming the pattern continues in a fixed way.
Australia, Italy, and Japan: where they fit in
Australia and New Zealand use the same band-and-cup system as the UK, so a UK 34C and an AU or NZ 34C are typically the same size with no conversion needed. Italy and Japan generally follow the EU centimeter-based band, though the details vary more by brand than the US-to-EU conversion does.
Some Italian labels use a simplified band scale of 1 through 6 instead of printing the centimeter number directly (Italian size 2 corresponds to EU 75, or US 34), while other Italian brands print the EU centimeter number on the tag as-is. Check which convention a specific label is using before assuming. Japanese sizing tends to follow the same centimeter-based band as the EU, with cup letters that generally line up with the EU and French scale, but several Japanese and other Asian brands run small through the cup. It is common, though not universal, to size up one cup letter the first time you try an unfamiliar Japanese label.
Why cup letters diverge above a D
Cup letters diverge above D because each country's sizing system was built independently, by different manufacturers, in different decades, and none of the resulting scales were ever reconciled. Through a D cup, US, UK, and EU labels agree completely: A is A, B is B, C is C, D is D. Past that point, a US DD becomes a UK E and an EU E. A US DDD becomes a UK F and an EU F. If you're several letters past D and trying to match brands across countries, check the specific brand's own conversion notes rather than assuming a G in one system is the same volume as a G in another. They frequently aren't.
Where bra sizing actually came from
There's no single global sizing standard because bra sizing itself was never invented once, by one company, in one place, at one time. Bra cup sizing wasn't standardized until the 1930s, and historians still disagree on who did it first. Formfit introduced three volume grades in 1932; S.H. Camp and Warner are both credited, in different sources, with inventing the letter system still used today. No single global standard followed, which is one reason US, UK, and EU sizes still don't line up.
That patchwork is still visible in every conversion chart you'll ever use, ours included. Each one traces back to a decision some manufacturer made nearly a century ago and never had to reconcile with what a competitor across an ocean was doing.
How to convert your own size, step by step
Start from your actual measurements rather than a size you've worn before, since your usual number only tells you what one specific brand decided to call your body.
- Measure your actual band and bust size at home rather than assuming your last purchase still reflects your current measurements.
- Once you have a band and cup in one system, US for example, use the tables above to find the equivalent number in whichever system the brand you're shopping uses.
- Check the specific brand's own printed size chart before ordering internationally. Small variations exist between labels even within the same country, and a chart with real band-and-cup numbers, like the ones on every product across our Bella, Carolina, Naomi, and Jia lines, is more reliable than a generic small, medium, or large label.
- If you land between two sizes after converting, size down on the band and up one cup letter, the same sister-sizing logic that applies within any single country's system.
Common mistakes when converting a bra size
The most common mistake is treating a US band number and an EU band number as if they sit on the same scale, when one is measured in inches and the other in centimeters. A few others show up just as often:
- Assuming cup letters transfer directly once you're several letters past D, when the systems frequently diverge there.
- Not noticing that some brands, Italian labels especially, mix numbering conventions on the same size chart.
- Ordering by an old, familiar size out of habit instead of re-measuring, particularly if it's been more than a year or your weight has shifted.
- Rounding a band measurement the way one country's chart rounds it, then applying a different country's chart to that already-rounded number instead of converting from the original measurement.
Frequently asked questions
Is a US 34C the same as a UK 34C?
Yes. US and UK bra sizes match exactly, band and cup, up through a D cup. They only start to differ above a D.
What is a US 34D in EU sizing?
A US 34D converts to an EU 75D. The cup letter stays the same through D. Only the band number changes, from the US and UK inch-based 34 to the EU centimeter-based 75.
Do Australian sizes need converting from UK sizes?
No. Australia and New Zealand use the same band-and-cup system as the UK, so a UK size and an AU or NZ size are typically identical without any conversion.
Should I size up when ordering Japanese lingerie brands?
Often, though not always. Several Japanese and other Asian brands run small through the cup, so many fitters suggest trying one cup letter larger than your usual size the first time you order from an unfamiliar Japanese label.
Why isn't there just one international bra size standard?
Because bra sizing developed independently across different manufacturers starting in the 1930s, and no international body has ever unified the systems that resulted. Each country's convention kept building on whatever its own early manufacturers decided, and that history is still baked into every size chart today.
Once you know your size in whichever system you're shopping, converting it should take thirty seconds, not another round of ordering and returning. Browse the full lingerie collection by band and cup rather than a generic size label, including matching panties and pieces from our Amber line for a complete set. If you're converting sizes for a wedding or honeymoon order, our Bridal Lingerie edit lists the same specific band-and-cup measurements on every piece, so there's no guessing involved there either.
About Lioness Studio. Lioness Studio is the editorial voice behind the Lioness Journal, written by the same team that handcrafts every made-to-order piece in the collection. We write about fit, fabric, and care because a well-made piece only does its job if it's sized correctly in the first place, in whatever system you're used to reading.
