I normally wear a size 6 and I ordered these Cayman's in a size 6 and they are a perfect fit for me. The size 7's fit my Granddaughter perfectly as well and she normally takes a 6-1/2. So if you're a single size order your size, if you're a half size, go up to the next full size. I wear the light weight garden "sloggers" around the house and these Cayman's are almost the same except with more holes for summer. They are roomy enough to be super comfy on the foot (with room to spare) and the strap touches only delicately on the back of the heel without irritation but yet still makes the shoe feel secure on your foot when you walk. AND I am also pleased with the "Pearl" color I chose over the white as well.  Pearl is a bit more subtle and has a bit more luster and richness to it than the bright whites.  Take note: the Khaki color in these Crocs, however is a bit darker than is pictured. To be honest they're more of a dark khaki which is going to work for me anyway but the color name should be changed to reflect these more accurately. I do LOTS of big box store shopping (Sam's-WalMart-Michaels-Home Depot-Lowe's etc.)not to mention Mall shopping and vacation shopping and walking sidewalks and my feet, legs and back take a pounding on all the concrete. I've already worn these and they have perfect support and comfort for such demanding walking. No more aching feet, sore legs and tired back!! ......................2015.............just received my next pair of Khaki Crocs (one shade darker than my previous pair but still acceptable as Khaki) and they arrived on time and with the fit I expected. I prefer inserts anyway in mine so they are as comfy as Crocs have always been for me. I have the khaki, chocolate, black, navy blue and the off white or cream that is no longer offered apparently.  In winter I wear the fleece lined crocs around the house. Still love these for long walks and shopping and for everyday.