Called Nike Fit, the tool – available as both in-store and at-home options – aims to address the problem of customers ordering and wearing the wrong-fit shoe.
"Three out of every five people are likely to wear the wrong size shoe," said Nike. "Length and width don't provide nearly enough data to get a shoe to fit comfortably. Sizing as we know it is a gross simplification of a complex problem."
The tool – which is a part of the existing Nike app – uses augmented-reality technology to scan your feet with a smartphone camera, mapping each foot's dimensions using a 13-point measuring system.
The sizing predictions are programmed using artificial intelligence, meaning that the more people use it, the more accurate it will become.
Nike hopes the tool will reduce the number of size-related returns and increase customer satisfaction.
To gauge the correct shoe size, users are asked to stand with their feet facing against a wall with socks that contrast with the colour of the floor. The frame is then calibrated by moving a line to mark the base of the wall. A photo is then taken of the feet using the phone camera.
The information collected is used to suggest the best fit for every shoe in Nike's catalogue, in UK, US and European size conversions.
"For example, if you have used Nike Fit to scan your feet and you go to purchase a Nike Cortez on the Nike app, you won't see a run of sizes anymore," said Nike.
"Instead, you'll just see your size for that particular shoe. Then, if you go to buy a Nike Air Zoom Pegasus you might see another size," explained the brand.
"That's because different shoes are made with different performance intent – a running shoe works best for the athlete when a little more snug while a sportswear shoe is designed to have more room for everyday wear," continued the brand.
These dimensions can be stored in the Nike Plus member profile and used for future online and in-store shopping.
Nike Fit will also be used in-store. Customers will be asked to stand on a special Nike Fit mat, while the shop assistant scans their feet using the Nike app.
There is also a guest mode where users can scan the feet of their friends and family: "Nike Fit will be great for parents trying to figure out what size cleat, basketball shoe or runner your little one needs this time," explained the brand.
The sportswear brand intends on developing the technology to create completely personalised products in the future. Earlier this year, Nike released a pair of smart basketball trainers with self-lacing technology.