The best way to know your shoe size is to measure your foot flat on the ground, from the back of the heel to the tip of your toes. It's even a good idea to measure both feet, as most of us have slightly different-sized feet. Then, compare those measurements in inches with standard shoe sizes to find yours. Alternatively, you can look for foot sizes on Etsy listing descriptions or even reach out to the small brand behind the shoes you have your heart set on for assistance.