The average shoe size for men in the United States is a size 9, and the average for women is a size 7. Shoe sizes vary slightly from country to country.
The average shoe size for men in China is a size 8. Women in China average a size 5.5 foot. United Kingdom men have a size 9.5 foot and women have a size 7. Men in Canada appear to have slightly larger feet than those in the U.S., and the average shoe size in that country is a size 10. Women in Canada average a size 6.5 shoe.
Shoe size is determined by the length and width of the foot. The size and shape of the foot changes over time so a shoe that fit 10 years ago may not fit well today. Many people have one foot that is slightly larger than the other, and when shopping for shoes, it is important to buy the size that comfortably fits the larger foot. Shoes that are too small cause foot pain and injury, and shoes that are too large cause blisters.
During the day, the foot swells due to sitting, standing and other factors. For the best fit when measuring shoe size, always measure at the end of the day, when the feet are at their largest.