This is exactly what StrutFit does: https://www.strut.fit/product https://www.strut.fit/product Live demo (click "What is my Vivobarefoot size? "): https://www

This is exactly what StrutFit does: https://www.strut.fit/product https://www.strut.fit/product Live demo (click "What is my Vivobarefoot size? "): https://www.vivobarefoot.com/uk/primus-lite-iii-mens-ss22 https://www.vivobarefoot.com/uk/primus-lite-iii-mens-ss22 Strut says they use AI, but that might just be marketing talk. You just need some optical image detection and basic math.