Bra Size Converter
Bra labels look very different from one country to the next, which makes shopping abroad or buying from an international site confusing. This converter clears it up by translating a US band and cup size into the equivalent UK, EU and French labeling using standard tables. The key is that the band and the cup are converted separately. The US and UK share an inch-based band, so the number stays the same between them, while the EU measures the underbust in centimeters, which makes a US 34 band an EU 75 band, and France offsets the EU centimeter band by adding 15, turning EU 75 into French 90. Cup letters line up closely across the US, UK and EU for the common A to D range, which this tool covers, though larger cups diverge and need a brand-specific chart. Pick your US band and cup and the converter shows the matching sizes in the other three systems side by side. Remember that fit varies by brand, so a converted size is a starting point rather than a guarantee. Every result is produced deterministically from the standard tables described below, with a worked example that reconciles exactly to the converter defaults so you can trust the translation before you order.
Band and cup convert separately: US and UK share the band, EU uses cm, France adds 15. A US 34C is a UK 34C, an EU 75C and a French 90C.
How the conversion works
UK band = US band (same inch number)
EU band = US band mapped to centimeters (34 to 75)
French band = EU band + 15
Cup letter carries across for the A to D range
The band and cup convert independently. US and UK share the inch band, the EU uses a centimeter band, and France offsets the EU band by 15. Cup letters align for A to D.
Worked example
Convert a US 34C to UK, EU and French sizing.
- UK band = US band = 34, so UK size is 34C
- EU band: US 34 maps to EU 75, so EU size is 75C
- French band = EU 75 + 15 = 90, so French size is 90C
A US 34C is a UK 34C, an EU 75C and a French 90C. These are the converter's default inputs, so the result above matches the widget exactly.
Band size across systems
The same band number in inches, centimeters and the French offset.
| US / UK | EU | French |
|---|---|---|
| 30 | 65 | 80 |
| 32 | 70 | 85 |
| 34 | 75 | 90 |
| 36 | 80 | 95 |
Measurement and sizing standards: US National Institute of Standards and Technology (NIST).
Bra size converter: frequently asked questions
How does bra sizing convert between countries?
The band number and the cup letter are converted separately. The US and UK use the same inch-based band number, while the EU uses a centimeter-based band (a US 34 maps to EU 75) and France adds 15 to the EU band (so EU 75 is French 90). Cup letters line up closely for the common A to D range across US, UK and EU; this tool uses standard tables for that range.
Why is the EU band a bigger number?
EU sizing measures the underbust in centimeters rather than inches, so the numbers are larger even though the physical band is the same. A 34 inch underbust is roughly 75 centimeters, which is why a US 34 band is an EU 75 band. France then offsets the EU centimeter band by 15.
Are cup letters the same everywhere?
Up to about a D cup the letters match closely across US, UK and EU systems, which is what this converter covers. Beyond D the systems diverge, with the UK and EU adding letters in a different sequence from the US (for example DD, E, F), so larger cups need a more detailed brand-specific chart.
Should I rely only on a converted size?
Treat the converted size as a starting point. Fit varies by brand and style, and the best practice is to measure your underbust and bust and try the size on. Use this converter to translate a size you already know works into another country's labeling, then check the fit.
How does the converter work?
It keeps the US and UK band equal, maps the US band to the EU centimeter band with a standard table, adds 15 for the French band, and carries the cup letter across for the A to D range using the standard correspondence.
Official sources
- Measurement, units and sizing standards: US National Institute of Standards and Technology (NIST). As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.