Order 1/2 size larger than your normal shoe. My first pair has  to be returned because it's smaller than my normal size. The toe box runs short and narrow. I think this is MTB's error in sizing them wrong.

Also, I agree with another reviewer that these are not made for women with calves! If you are athletic/have muscles from walking, running, cycling, etc., they will be very tight at first and hard to zip. There is some give and they will stretch within reason after being broken in. It seems the company only tried these for size using skinny, teen aged, fashion-model-type women.

These are beautiful, if expensive, boots. I must wear only negative heel shoes due to a intermetatarsal neuroma. They allow me to walk without pain.

 I'm ordering a pair in each color, the sale on these for 1/3 the normal high price is too much to resist. Negative heel boots are very hard to find! MTB's well made and very comfortable, once your fit is established. The prices are super high. I've waited for these to go on sale. If you are reluctant to pay so much, watch for sales!

For less expensive but good quality negative heels, try Sketchers Shape Ups and "Earth" brand. For an almost exact copy of this style, but in a vegan "patent leather" material (MTB's are real leather), look for Earth Women's Elite. They cost $99, come in several bright and shinny colors, and run true to size in fit.