I took a chance with these boots. I wear a size 12M (although NW shoes/boots are most times slightly roomier width). My calf is 17in. So I checked with NW & verified the shaft of this boot because information shows it is 15 1/2 inches wide for size 8. They told me it would be 16 1/2 for size 12. With free ship & returns it was worth a try. It fits my calf! It could stand another inch in my opinion. I figured they would probably give that inch as I wear them because they are leather. I walked around in them to be sure and they are very comfy and easy to walk in (on carpet but the true test is concrete). I ordered the black and the leather is quality, smooth and rich (perfect match for my black leather coat). I gave it 4 stars because I just wish the heel was a little thicker for stability purposes (I'm not too fond of skinny stilleto heels). Other than that the boots are fab!