Remove the shoe from your right (or longest) foot. Measure with sock if you want space or no sock for a tighter fit. Place a blank sheet of paper against the wall and stand on it with your heel against the wall. Mark straight down from the longest toe on the paper. Measure from the edge of the paper against the wall to the line marked on the paper. Use the sizing chart below to match your measurement with an accurate size.
Note: If you're between sizes and looking for comfort, then it is generally recommended to round up. If you are after more of a performance fit, then round down.