A monospaced font, also called a fixed-pitch, fixed-width, or non-proportional font, is a font whose letters and characters each occupy the same amount of horizontal space. This contrasts with variable-width fonts, where the letters and spacings have different widths. For example, the two high-use letters "I" and "E" do not need the same footprint. Both letters differ in center-to-next-letter edge (and center-to-center) spacing distance needs (margins) in variable width fonts. The variable that changes is offset from what would otherwise be monospaced centering. In a modern proportional font, every dimension can be scaled and changed, but such sizing mathematically must still maintain monospacing or variable spacing.