These fit pretty snug around your calves, if you have calves that usually don't fit tall boots, I don't recommend these for you. If you do, please size up. In many of the reviews I've seen on Amazon (selling this exact brand and boot), all the reviewers have mentioned to size up (if you wear a size 8, order a size 9) which I did, and it fits like a regular US size 8. It's made of rubber and waterproof all over so I can walk my dog in puddles and mud whenever without worrying about my socks getting wet or the back of my pants getting too muddy. I also highly recommend some knee-high socks with these boots, it helps with the sock slippage (there's less, as to when you might just wear no-shows or ankle socks).