Generally speaking, longer shirts or shirts with a higher button placement will have more shirt buttons on the front. The exact logic is complicated to explain, so we updated the sizes interface to calculate and display the number of buttons that will be on the front of the shirt based on the shirt length and top button placement.
As of June 4th, 2020, we updated our system to automatically adjust the distance between the buttons (not counting the collar button) based on the Top Button Placement, the Back Length, and your Posture setting.
Button Spacing options are 3 1/8″ (3.1″), 3 1/4″ (3.3″) or 3 1/2″ (3.5″). We dynamically change this to help maintain an optimal placement for the bottom button that is not too close or too far from the bottom of the shirt.