Blouse Size Conversion Chart

Conversion table

The table below is a commonly used starting conversion. Bust ranges are broad adult ranges in inches, labelled as starting ranges rather than exact brand measurements. Use your own bust measurement to pick a row, then check the row against the brand chart for the blouse you want.

Read the table row by row, not column by column. Pick the row whose bust range contains your measurement, then read across to the system you need. If your bust sits on a boundary between two rows, note both rows and use the shape rules in the between-sizes guide to choose, rather than rounding blindly.

US and UK: the two number gap

US and UK numeric sizes differ by two in most charts: a US 4 is a UK 8, a US 8 is a UK 12, a US 12 is a UK 16, and so on. The gap is steady across the table, which makes US to UK conversion the most reliable of the three systems. It is still only a starting point, because a brand that grades generously in one market can shift a row, but the two number rule holds for most mainstream charts and is a good first check.

A common error is to treat a UK size as a US size and order two sizes too small. If a listing shows only one numeric size without saying which system it uses, check the retailer location and the chart heading before ordering. A UK retailer listing a 12 usually means UK 12, which is US 8, and the difference matters.

EU sizes run higher

EU sizes look much larger because they are built on a different numbering base, roughly body measurements in centimetres halved, rather than a small dress size scale. A US 8 commonly converts to EU 40, a US 12 to EU 44, and a US 16 to EU 48. The steps are two at a time, matching the two step pattern in US and UK sizes, just from a higher starting number.

EU charts also vary by country in small ways, and some EU brands use their own letter sizing alongside numeric sizes. When a listing gives both, trust the numeric row that matches your bust range over the letter, because letters group two numeric sizes and can hide a boundary case.

Letter sizes group two numbers

Letter sizes are broader than numeric sizes. In most charts, extra small covers US 0 to 2, small covers US 4 to 6, medium covers US 8 to 10, large covers US 12 to 14, extra large covers US 16 to 18, and double extra large covers US 20 to 22. That grouping is convenient for relaxed blouses, where a little extra room does not matter, but it is risky for fitted blouses, where the difference between the two numbers in a letter can mean button gaping or a loose waist.

When a blouse is sold only in letter sizes, choose by bust range rather than by the letter you usually wear. A usual medium in one brand can be a small or a large in another, because the letter boundaries move with brand grading. The bust range in the table above is the anchor, not the letter.

Brand grading caveat

Every conversion table, including this one, is a summary of common practice, not a promise about one brand. Brands grade patterns from a base size outward, and the steps they use differ slightly, especially at the ends of the range. A brand aimed at a taller customer may grade longer, while a brand aimed at a petite customer may grade shorter, and neither change shows up in a conversion table.

Use conversion to narrow the choice to one or two sizes, then confirm with the brand chart for the exact blouse, using your bust measurement. If the brand chart disagrees with the conversion by one size, trust the brand chart, because it describes the garment you are actually buying.

Worked example

Take a bust measurement of 36 inches. In the table, 36 falls in the medium row, bust range 35-37, which reads US 8 to 10, UK 12 to 14, EU 40 to 42. For a fitted blouse, favour the upper end of that row, US 10, UK 14, EU 42, because a fitted shape needs room across the bust. For a relaxed blouse, the lower end, US 8, UK 12, EU 40, can work, because the cut carries spare fabric. Either way, the conversion gives a starting pair of sizes to check against the brand chart, not a final answer on its own.

Converting from a usual size

Converting from a usual size is weaker than converting from a measurement, because a usual size already contains one brand grading. If you know you wear a US 10 in one brand, converting that to UK 14 is reasonable, but it carries that first brand grading into the second brand. Where possible, go back to your bust measurement and convert from there, so the new brand chart is the only grading in the result.

Frequently Asked Questions