UK vs US Bra Sizes

What stays the same

Both countries size bands in inches and use the same even numbers: 30, 32, 34, 36 and so on. A UK 34 band is a US 34 band.

Cups AA, A, B, C, D and DD are also shared. If you wear a 34C or a 36DD, the label is the same on both sides of the Atlantic, and you can stop reading here.

Where they split

Both systems add one cup for each extra inch of difference between bust and band. They simply name the steps differently once they pass DD.

The UK inserts a double letter after most single ones (F then FF, G then GG, H then HH) and has no I cup. The US moves through single letters. Because the UK fits two sizes under each letter where the US fits one, the systems drift further apart the higher you go. At a UK G the American letter is already two places further along the alphabet.

The traps

The same letter, different sizes

F and G appear in both systems and mean different things in each. A US F is a UK E. A UK F is a US G. If you order "your usual 34F" from an American brand without converting, the bra will arrive one cup too small.

American brands do not agree with each other

UK sizing is fairly consistent between brands. US sizing above DD is not. One brand calls the 6-inch cup DDD and another calls it F. Some continue DDDD, others G. The table above shows the most common pattern, but when a US brand publishes a size chart, trust the chart.

British brands sold abroad keep UK sizes

Panache, Freya, Curvy Kate and other UK full-bust brands are sold widely in the US in their original UK sizing. An American shopper who is a US 32G needs a UK 32F in those brands. If you are a UK shopper reading American reviews of British bras, the reviewer may be quoting either system.

Labels with several sizes on them

Many bras carry a label listing UK, US, EU and French sizes together. Read along to the UK entry, and do not assume the first or largest one is yours.

How to tell which system you are looking at

• FF, GG, HH, JJ or KK: UK. No other system uses them.
• DDD or DDDD: US.
• An I cup: US or European. UK sizing skips I.
• A band of 60 or above: European or French. See the international chart.
• None of the above: check where the brand is based, or its size guide.

Buying from a US brand as a UK shopper

1. Start from your UK size, ideally one confirmed by a bra that fits you now.
2. Keep the band number.
3. Convert the cup using the table above, or the UK to US converter.
4. Compare with the brand's own chart if it has one, and go with the chart where they differ.
5. Check the returns terms before ordering. Cut varies between brands in any country, so a correct conversion can still need exchanging for the next cup.

Why are they different at all?

No international body sets bra sizes. Cup letters were introduced commercially in the United States in the 1930s and each market extended them in its own way as manufacturers began making larger cups. British makers settled on alternating single and double letters. American makers extended DD into DDD and then carried on through the alphabet. Neither approach is more correct. They are two labelling conventions for the same series of one-inch steps.

Frequently asked questions

Are UK and US bra sizes the same?

The bands are the same, and the cups are the same from AA to DD. Above DD the letters differ. A UK E is a US DDD or F, a UK F is a US G, and the gap widens with each cup after that.

Is a UK DD the same as a US DD?

Yes. DD is the last cup the two systems share. The next size up is called E in the UK and DDD (or F) in the US.

Which is bigger, a UK F or a US F?

A UK F is bigger. A US F is the same as a US DDD, which is a UK E. A UK F is one cup larger than that, and equals a US G.

Do US brands sold in the UK use UK sizes?

Not reliably. Some relabel for the UK market, some print both, and some keep US sizing. Check the size guide on the product page, and look for DDD on the label, which only exists in US sizing.