International sizing is a mess. A US women size 8 shoe is a UK 6, an EU 39, a JP 25, and an AU 6.5. There is no universal standard, and every region has its own numbering system rooted in different measurement traditions. When you are shopping from an overseas brand, browsing an international marketplace, or simply trying to order the right fit online, getting the conversion wrong means returns, wasted money, and frustration.
MySizeIs was built to solve exactly that problem. Every converter on this site runs entirely in your browser. There is no server processing your data, no account to create, and no paywall hiding the results. You enter a size or a measurement, and every equivalent region updates instantly.
Each converter is backed by lookup tables sourced from the official sizing standards of each region. For shoes, that means the Brannock system for US sizes, Mondopoint for JP, and the Paris Point system for EU. For rings, we use the standard inner-diameter tables published by jewelers associations. For bras, we reference the band and cup progressions defined by each region (including the notoriously different FR and JP systems). Where sizes fall between standard values, we use linear interpolation to give you the closest half-size rather than rounding arbitrarily.
Most size conversion sites fall into two categories: outdated tools with aggressive advertising that make finding a simple answer painful, or freemium platforms that hide useful features behind signup walls. MySizeIs takes a different approach entirely. The site loads fast because every page is self-contained, static HTML. There are no frameworks, no third-party trackers beyond basic analytics, and no pop-ups asking for your email. Ads are present but never placed between the converter input and its results, because the tool is the point, not the ad.
The design is intentional too. Size conversion is a quick, utilitarian task. You should be able to get your answer in under five seconds and move on with your shopping. Every converter follows the same layout: input at the top, results below, reference chart underneath for context. No tutorials, no onboarding, no friction.
MySizeIs is part of a growing portfolio of free utility sites, each focused on doing one category of tasks exceptionally well. If you have used Kaalq for calculations or SleepCalcs for sleep tools, you will recognize the same philosophy: genuinely free, fast, and respectful of your time.
Have a suggestion or found an inaccuracy in one of our charts? Reach out at hello@mysizeis.com and we will look into it.