Proper Foot Placement in Newtons
There's more to Newton sizing than just checking where your toes are!
Accurate sizing is essential for proper shoe function and to avoid injury.
Flex point/arch length: The joint of your big toe should fit approximately in the middle of the flex panel on the inside of the shoe. This places the flex point of your foot, where your toes bend up, over the four external lugs on the bottom of the shoe.
Width: Your foot should not spill over the sides of the shoe when you stand and put weight on the ball of your foot. Remember your foot spreads and swells as you run. Your running shoe is likely to be larger than your dress shoe, possibly up to a full size larger.
Length: You need at least ¼ - ½ inch of room between the end of your longest toe and the inside of the end of the shoe, preferably more. This can be up to a full inch if you have a very long arch and/or very short toes.
Volume: You should be able to comfortably lace your shoes.
