Why we built it
Clothing sizes are inconsistent. A Medium in one brand is a Large in another, and a UK 10 is not a US 10. Returns are frustrating and wasteful, so we built SizeWise AI to take the guesswork out of ordering clothes and shoes online.
What SizeWise AI does
- Size converter — convert between US, UK, EU and other sizing systems for clothing and shoes.
- Brand guides — see how brands such as Nike, Zara and H&M tend to fit.
- AI fit predictor — describe your measurements and the item, and get a recommended size.
- Blog — plain-English guides on sizing and fit.
How the AI works
Our AI features are powered by a large language model (OpenAI's GPT-4o mini). It combines general sizing knowledge with the details you enter to give a suggestion. These are estimates: brands change their sizing, and cuts vary between styles, so always check the retailer's own size chart before buying.
Free to use
SizeWise AI is free. The site is supported by advertising, which helps cover hosting and AI costs. See our Privacy Policy for details.
Get in touch
Found a wrong size or have a suggestion? We'd love to hear from you on our contact page.