If I wear a size 9 in the us what is it in a UK size?

If you wear a size 9 in US shoe sizing, it typically converts to a size 8 in UK sizing. This is because UK sizes are generally one size smaller than US sizes for men's shoes, and about 1.5 sizes smaller for women's shoes. However, it's always a good idea to check specific brand size charts, as sizing can vary slightly.