The Brannock device: that metal contraption in shoe stores that looks like it was invented the same decade as the jukebox. It’s old-school, not sexy, and still one of the best first steps you can take toward getting boots that actually fit.

But it’s not magic. It’s a measuring tool. A good one. With limits.

Let’s get clear on what it is, what it measures, and why it can still leave you with a boot that feels “fine in the store” and awful by kilometer five.

Shoe sizing isn’t universal. It’s three major systems (US, UK, EU), plus brand-specific quirks stacked on top. So when someone says “I’m a size 10,” what they really mean is: “I’m a 10 in the one brand I’ve been buying since 2008.”

This post breaks down what each system is, how they differ, where they’re used, how width works in each, and how to convert between them without treating a chart like it’s scripture.