The Francesca slippers are available in whole sizes (6-11) and select half sizes (7.5, 8.5, 9.5) in standard medium width. They generally fit true-to-size (but everyone's feet are different!).

US 6 7 7.5 8 8.5 9 9.5 10 11
UK 4.5 5.5 6 6.5 7 7.5 8 8.5 9.5
EU 36.5 37.5 38 38.5 39 39.5 40 40.5 41.5
JP 23 24 24.5 25 25.5 26 26.5 27 28