Gavin cycling shoes run true (to slightly small) to EU sizes, however please know that converting between US and EU sizes is not exact size for size match. A US size can fall between two EU sizes.
If you are unsure which shoe size would be a good fit for you, the best thing to do is to be measured at a local bike shop or shoe store. This will give you the exact size you need. The next best thing to do is lift your shoe tongue and look for the corresponding EU size with your US size. If you are trying to decide between sizes, we would suggest ordering the next size up, as you can always wear thicker socks.