Uk to Us Dress Size Converter

UK women's dress sizes run 4 numbers higher than US sizes. UK 6 = US 2, UK 8 = US 4, UK 10 = US 6, UK 12 = US 8, UK 14 = US 10, UK 16 = US 12, UK 18 = US 14, UK 20 = US 16. The calculator covers UK 6 through 20, the standard British high-street range. If you wear a UK 12 from Marks & Spencer, you would order a US 8 from a brand like J.Crew or Banana Republic.

The 'minus 4' rule holds across the whole high-street range, but breaks down at extremes. Petite sizing in the US uses different numbers (the 'P' suffix denotes 5'4" and under), and plus sizing above US 16/UK 20 is labelled in different ways depending on the brand (1X, 2X, 3X in some American brands). The calculator handles the standard range; outside it, always check the brand's own size guide because labels become inconsistent.

Both UK and US sizes have drifted larger over the last 30 years through 'vanity sizing': the practice of relabelling a slightly larger garment with a smaller number so the customer feels good. A UK 12 today has a 92 cm bust; a UK 12 from a 1980s pattern book had an 86 cm bust. US sizes have drifted even more aggressively because of the cultural premium on small-number labels. So a US 4 in 2026 is genuinely roughly the same as a UK 8 in 2026, but a 1990s US 4 was substantially smaller.

This is why measurements (bust, waist, hip in cm or inches) are more useful than size labels when ordering across markets. Most reputable retailers (Nordstrom, Net-a-Porter, ASOS) publish a size chart with cm values alongside the size labels. Use those values, not the number, to pick. The [clothing size converter](/clothing-size-converter) handles a wider range of size systems including dress, tops, trousers and outerwear.

EU dress sizes are roughly UK +28 (a UK 10 is an EU 38). Italian sizes (Diesel, Prada, etc.) are roughly UK +30 (UK 10 = IT 40). French sizes match EU. Spanish and Portuguese brands often use a mix. The calculator's UK-to-US conversion is the cleanest of these because the two countries' systems share a similar history; conversions to continental sizes need a separate lookup, which the [UK to EU dress size](/uk-to-eu-dress-size) converter handles.

Worked example: A UK 12 dress is a US 8, an EU 40 and an IT 42 (some sources say IT 44; Italian sizing varies brand to brand more than any other system). Buy from a brand once, take note of which size in their range fits, and stick with that brand. The number on the label tells you less than how that specific brand cuts.