Please take the measured foot length as the standard, the actual foot length depends on the measured foot length and then tell the shoe seller to let the shoe seller match the size, the shoe size is only for reference!
Different brands of shoes, especially sneakers and sports shoes, although the label size is the same, but due to the difference in shoe shape, there may be a difference of half a size. And single shoes may need to be half a size larger than the usual size of sports shoes due to the thin and long soles. Snow boots need to be half a size or one size larger than usual because of the thick layer of fluff inside.