What a UK size 12 measures at 27 retailers

The hips differ most. The lowest size 12 hip figure was 99 cm (Bonmarché and Kaleidoscope) and the highest was 108 cm (Rixo), a difference of 9 cm. Most retailers step up by about 5 cm from one size to the next, so that is close to two sizes.

The waist differs by 6 cm. The lowest size 12 waist was 74 cm (Monsoon) and the highest 80 cm (Oliver Bonas).

One retailer's 10 is another's 12. Oliver Bonas publishes 92, 75, 100 cm (bust, waist, hips) for a size 10. Marks & Spencer publishes the same three figures for a size 12.

Some charts are identical. Boohoo, Dorothy Perkins and Warehouse publish the same figures for every size we compared, so the 26 retailers do not mean 26 different charts.

These are the body measurements each retailer says a size is designed to fit, not the measurements of the clothes. None of this says one chart is right and another wrong. It shows that the number on the label only has a meaning next to that retailer's own chart.

No law fixes what a size 12 is. The British and European standard for size labelling, BS EN 13402, describes how to label clothes by body measurement, but using it is voluntary and it does not define the UK numbered sizes. Each retailer decides who its customer is and grades its sizes around that person.

For shoppers this means the chart matters more than the label: measure yourself once and compare with the retailer's own figures. Our clothing size converter covers UK, US and EU labels, and what "true to size" means explains fit notes.

For retailers it is a reason to publish the chart as text that people and machines can read. In our Shopify Size Chart Report 2026, 31.6% of 829 fashion stores had a size chart readable as text. A shopper who cannot find the chart falls back on the label, and the label means different things in different shops. You can check your own store with the free size chart audit.

What we read. On 12 November 2026 we opened the public women's size guide of each retailer and copied the body measurements for bust, waist and hips for each UK size. Every row links to the page we read. We did not estimate, average or fill in any figure.

Which retailers. 27 UK fashion retailers and brands whose size guide gave body measurements as text for numbered UK sizes. This is not a random sample and not a market-share ranking. Several large retailers are missing because their size guide did not load for an automated reader or gave no body measurements; we did not work around any site's access controls. No Rendered Fits customer is included.

Units. Figures are in centimetres as published. Where a retailer published inches only, we multiplied by 2.54 and say so in the row. Inch figures in the table are converted from centimetres and rounded to one decimal place.

Ranges. Boden publishes a range for each size. Its figures are shown in the tables but left out of the lowest, highest and middle values, which use the 26 retailers that publish one figure per size.

Limits. Retailers measure the hip at slightly different points and label it "hip", "full hip" or "low hip"; the row notes give the label where it differs. A body measurement is not a garment measurement. Charts change, some retailers use different charts for petite, tall or curve ranges, and brands sold on a retailer's site may use their own. Treat this as a dated snapshot of each retailer's main women's chart.

Updates. When we read the charts again we will publish the new figures with a new date and keep these.