In reply to kyaizawa:
Yep, as above. 2 to 2,5 UK sizes down depending how hardcore you are.
Unlined leather slippers take some work to get them to fit you well. If you can put them on first go then they are too big. It should be a fight to put them on, which can be made easier by wearing plastic bags, but after a week or so they'll have stretched to your feet and will be like gloves.