About MySizeCharts

Why this exists

Every jewelry brand, shoe maker and clothing label publishes its own size guide, and each one only shows its own products in its own home market. If you are buying across borders or comparing brands, that leaves you stitching together half a dozen incompatible charts. MySizeCharts solves that by being neutral: one set of tables that maps US, UK, EU and international sizes to the physical measurement underneath, so any label can be read against any other.

How the tables are built

Every conversion is anchored to a real physical dimension. Ring sizes come from the inside diameter and circumference of the band in millimetres. Shoe sizes come from foot length in centimetres. Hat sizes come from head circumference, bra sizes from underbust and bust, and clothing from chest, bust and waist. Because the labels all describe the same measurement, the conversions are exact rather than approximate.

Where a published international standard exists, it is named on the chart page itself rather than referred to in the abstract. Ring sizes follow ISO 8653, shoe sizes follow the Mondopoint system of ISO 9407, and body measurements follow ISO 8559-1 and EN 13402. Where no standard exists, and for hats, belts, socks and bras there is none we know of, the page says so in as many words. The full reasoning, including how each number is rounded, is on the methodology page.

Who maintains this

MySizeCharts is built and maintained by Jamey Weber, engineer and maintainer at FusionStudios.

Jamey Weber builds and maintains MySizeCharts at FusionStudios. He is not a fit specialist and does not claim to be. Every table here is derived from a physical measurement and, where one exists, a published international standard, and every reader correction is checked against that same source before it is applied.

That is the honest version, and it is deliberately not dressed up. What makes a sizing reference trustworthy is not a credential on an about page but a named person, a stated source per number, a visible date, and a correction that actually gets made. All four are here. If you find something wrong, hello@mysizecharts.com reaches a human, and corrections land in the changelog with a date.

How it stays accurate

Each data page carries a last-reviewed date and names the person who reviewed it. The changelog records what changed and when, including corrections: the entry of 25 July 2026 records two, one about the UK to US shoe offset and one about the sock medium range. Sizing standards move slowly, but brand conventions drift, so the note stays honest: the charts are a reliable starting point, and you should always confirm a specific brand fit before you buy.

Free to use, private by design

There is no sign up and no paywall. Every converter runs in your browser using static tables built into the page, so nothing you type is sent anywhere. For developers, the same data is available as a free JSON API, and the converter can be embedded on any site.

Not to be confused with

MySizeCharts is not affiliated with MySize Inc. (NASDAQ: MYSZ) or with mysizeid.com. Those are a separate, listed company and its product, working in the same field. This site is an independent free reference built by FusionStudios, and it has also been published under the shorter name SizeCharts.