Why are UK and US cup sizes different?

The two systems share A to DD, then diverge: UK continues E, F, FF, G, GG, H while US continues DDD, F, G, H, I, J. This converter keeps the cup letters aligned to the same physical volume automatically.

What is a UK E cup in US sizing?

A UK E cup corresponds to a US DDD at the same band, because the US ladder inserts DDD where the UK ladder uses E. Choosing UK as your system makes the tool show the matching US letter.

How do EU bra band sizes relate to inches?

EU bands are measured in centimetres, so a 32-inch band is EU 70, 34 inches is EU 75, 36 inches is EU 80, and so on in steps of five centimetres.

How are FR and AU/NZ sizes derived?

The FR/ES band is the EU band plus 15 (so EU 75 is FR 90), while the AU/NZ band uses its own even-number scale (32 in = AU 12) with the UK cup letter.

Should I size by band or by cup first?

Both matter together: the band sets the number and the cup sets the letter. This tool converts a complete band-and-cup size, since changing one without the other gives a different fit.

Why might my converted size still not fit?

Brands and styles vary, and cup volume changes with band size (sister sizing). Treat the result as a confident starting point, then try the neighbouring sizes.

Is my size sent anywhere?

No. The conversion tables are built into the page and run only in your browser.

Bra Size Converter — Gera Tools

Bra size converter

Bra sizing changes a lot between countries — and UK and US cup letters diverge above a D cup, which trips up most charts. This converter aligns the cups by physical volume so the equivalents are correct, then shows your band and cup in UK, US, EU/DE, FR/ES and AU/NZ.

How it works

You pick whether your size uses UK or US cup letters, then a band (in inches) and a cup. The band maps to fixed equivalents: each inch band corresponds to an EU centimetre band (32 → 70, 34 → 75, in 5 cm steps), an AU/NZ band, and the FR/ES band, which is simply the EU band + 15. The cup letter is mapped through aligned UK and US ladders so the same physical cup keeps the right letter in each system.

Example

A UK 34C:

System	Size
UK	34C
US	34C
EU / DE	75C
FR / ES	90C
AU / NZ	12C

For a size where the systems diverge, a UK 34E converts to a US 34DDD. Brands still vary, so treat the result as a starting point. Nothing you enter leaves your browser.