US to UK Dress Size Conversion
| US | UK |
|---|---|
| 0 | 4 |
| 2 | 6 |
| 4 | 8 |
| 6 | 10 |
| 8 | 12 |
| 10 | 14 |
| 12 | 16 |
| 14 | 18 |
| 16 | 20 |
Sizing conventions vary by brand and by cut — this table shows the standard published conversion. Always check the garment's own size chart when one is available. See how these tables are compiled.
A consistent four-number gap with an inconsistent cause
US and UK women's dress sizes both use an even-numbered scale (0, 2, 4, 6...), and on the standard published chart the two are a steady four numbers apart — a US 6 is a UK 10. That gap looks like it should be simple arithmetic, but it isn't purely a labeling offset: US sizing has drifted through decades of 'vanity sizing', where brands have gradually labeled the same actual body measurements with smaller numbers to flatter buyers, while UK sizing has drifted somewhat differently and, on average, less aggressively over the same period.
That means the four-number gap you'll find on a size chart today isn't the same gap you'd have found decades ago, and it isn't identical brand to brand even now — a fast-fashion US label that has sized down aggressively over the years can require a bigger jump than four numbers to reach the equivalent UK size, while a more conservative US label might convert closer to the historical four-number rule.
Cut assumptions differ as much as the numbers do
Beyond the raw size number, US and UK dress patterns are commonly drafted around slightly different assumed bust-to-waist-to-hip ratios, reflecting different historical body-shape data each country's pattern-making tradition was built on. A dress converted correctly by size number can still fit differently through the waist or bust than a UK-drafted dress of the nominally equivalent size, particularly for fitted or structured styles where the underlying block matters more than for loose, flowing ones.
What actually settles a sight-unseen order
Checking the specific brand's own bust/waist/hip measurements in centimetres or inches against your own is far more reliable than applying the standard four-number rule, especially for a brand you haven't bought from before — the size-number conversion gets you in the right general area, but vanity-sizing drift and differing cut assumptions mean it's a starting point, not a guarantee.
Bridal and occasion wear behave differently
Bridal, bridesmaid, and formal occasion dresses are commonly sized on a separate, often smaller-running scale than everyday ready-to-wear from the same country, because these categories are traditionally made to a tighter fit for photographs and are expected to be tailored afterward. Converting a US bridal size to UK using the standard everyday-dress offset is a common mistake — check the specific bridal retailer's own chart, which usually runs its own numbering distinct from that brand's regular clothing line.
Petite and tall ranges add a further variable, since a UK retailer's petite line and a US brand's regular line aren't sized on directly comparable proportions even once the size number is converted — the number conversion addresses girth measurements, not the vertical placement of the waist or hem, which petite and tall ranges specifically adjust for.
Frequently asked questions
Is the US-to-UK dress size gap always exactly four numbers?
It's the standard published rule, but decades of vanity-sizing drift, which hasn't moved at the same rate in both countries, means some brands now require a bigger jump — check the brand's own measurements for anything you can't try on.
Why does a UK-sized dress sometimes fit differently even at the 'correct' converted size?
US and UK dress patterns are often drafted around different assumed body-shape ratios historically, so a correctly converted size number doesn't guarantee an identical fit through the bust and waist, especially in fitted styles.
Does vanity sizing affect UK sizing as much as US sizing?
Less so on average — US mainstream sizing has drifted toward smaller numbers for the same body measurements somewhat more aggressively over recent decades than UK sizing has, which is part of why the standard four-number gap isn't perfectly stable across brands.
Should I trust a vintage US dress size's UK conversion?
Be cautious — an older US size reflects the body measurements that number represented at the time, which were typically larger than today's equivalent US number, so converting a vintage size with a current chart can undersize the result.
Does the standard four-number offset apply to bridal or formal dresses?
Not reliably — bridal and formal wear are traditionally sized smaller and closer-fitting than everyday clothing from the same brand, with their own separate size chart, so use that specific chart rather than the everyday-dress conversion.
Does converting my US petite size to UK sizing account for height as well as girth?
No — the size-number conversion only addresses girth measurements like bust and waist; petite and tall ranges separately adjust vertical proportions like waist placement and hem length, which the conversion doesn't capture.