About this tool
Enter your waist and inseam (leg length) in inches or centimetres to get a jeans size. The headline is the W×L number used in the US and UK — waist inches by inseam inches, such as 32×34 — alongside the European size, a UK number and the S/M/L letter equivalent. It all runs in your browser from a built-in chart; nothing is sent anywhere.
The W is your waist measurement in inches, rounded to the nearest whole inch, and the L is your inseam in inches; together they give W×L. The other systems come from a static waist-inch conversion chart: European jeans sizes run roughly ten above the inch waist (a 28" waist is about an EU 38, a 32" waist an EU 42), the UK number sits about eighteen below it, and the letter size groups waists into ranges (about 26–27" = S, 28–30" = M, 31–33" = L).
Measure your waist where you actually wear the jeans, and take the inseam from the crotch seam down the inside leg to the hem of a well-fitting pair. Denim is cut in many rises and styles and vanity sizing is common, so these figures are approximate and vary by brand — check the label's own chart before ordering.