I always order a size up on these as actual size for me is a bit small or to perfect.  One size up keeps my entire foot on the flip flop.  Id give these a 5 star but I do have to replace these every couple years as they alway rip in the same place which is the piece that goes between the toes.  It usually stretches out or snaps and become a loose fit which gets uncomfortable trying to keep them on.  One thing is even though they do this I re-buy the same brand.  I can walk all day in Disneyland in these flip flops.