What size-related returns cost you
A wrong size is the most expensive kind of sale: you pay to ship it out, you pay to ship it back, you pay someone to inspect it, and often you sell it again at a discount or not at all. Put your own numbers in below and see the annual figure.
Everything above is computed in your browser from the numbers you typed. Nothing is sent anywhere and nothing is stored. The figures are only as good as your inputs, and no industry average is filled in for you on purpose: a benchmark without a source is a guess with a currency symbol in front of it.
What actually moves that number
Four things, roughly in order of how much they help and inversely in order of how much work they are.
- Put the answer on the product page. A customer who has to leave to find out what an EU 39 is may not come back, and if they guess they will sometimes guess wrong. The free converter widget is one iframe and does this in five minutes.
- Publish a body measurement, not only a label.Foot length in centimetres, chest in centimetres, underbust and bust. A label is your convention; a measurement is a fact the customer can check against themselves. This is also the single thing that makes your chart comparable to anyone else's.
- Say where your fit differs."This model runs about half a size small" on the product that does costs you nothing and prevents the return outright. Silence about a known fit quirk is a return you have already paid for.
- Read your own reason codes. Most shops know their return rate and not their return reasons. One quarter of reason-code data tells you which products cause the problem, and it is almost never spread evenly.
What MySizeCharts gives you for free
- The converter widget, configurable by category and direction, with install guides for Shopify, WooCommerce and Squarespace.
- The JSON API: every table as static JSON under CC BY 4.0, no key, no rate limit, so you can build the conversion into your own product page.
- The methodology, so you can check what our numbers are anchored to before you put them in front of your customers.
None of that is a trial. It is free because a neutral reference is worth more to us when it is used than when it is metered.
Common questions
What share of returns is size related?
It depends entirely on what you sell, and anyone quoting you a single figure for all of ecommerce is quoting a number they cannot support. Footwear and fitted apparel sit far higher than accessories. Your own returns data has the answer: read the reason codes for one quarter and use that share in the calculator above.
Does a size chart actually reduce returns?
A chart on its own does less than people hope, because the customer has to find it, read it and trust it. What moves the number is putting the answer where the decision is made: the size in the system the customer already knows, on the product page, without a click.
Is the converter free for commercial use?
Yes, including on a shop that sells. The widget asks only that you keep the small attribution link. There is no plan, no seat, no usage limit and no trial that ends.
Can I use my own size tables instead?
The free widget uses the neutral tables published on this site. If you need your own measurements in it, or the converter built into the product template rather than an iframe, that is custom work and FusionStudios does it.
Last reviewed and updated on August 5, 2026. Conversion tables are checked against published international sizing standards.