I purchased two pair of these. The first I followed US sizing - I am a 9 so I purchased the 9 even though I am usually an EU 40.  First pair - way too small. I ordered the second pair in a US10/EU40. Almost fit but still small. I think a 41 will be too large but I may give it a go (third time a charm?). I wish more shoe manufacturers would produce half sizes. However, very cute, cushy for a ballet flat and "stay-on" power with the nice elastic strap.

Follow up, pair 3:  Way too big! I knew before I ordered but hoped for a fit. The first two pair were just the right width but too short. The last pair was too wide and too long. Guess I am not a happy Camper :D