ANSI and ISO represent two different world standards organizations, ANSI is the American National Standards Institute, ISO is the International Organization for Standardization; the keyboards of these two layouts are different in key size and position, and are also different from QWERTY, Colemak, Dvorak and other layouts. Different; the difference between the two keyboards is mainly in the size and position of the Enter, Backslash, and Left Shift keys.

The ISO layout keyboard is more popular in Europe, because the ISO layout keyboard has the Alt Graph (also known as AltGr) key, it is more convenient to enter characters with diacritics, using the Alt Graph key can enter the third umlaut of the character, Combining Shift and Alt Graph can enter a fourth umlaut, which is not something an ISO keyboard can do.

The most obvious difference between ANSI and ISO layouts is the left shift key. In the ANSI layout, the left shift key is a large and wide rectangular key. In the ISO layout, there are two keys in the position of the left shift key. The left of these two keys is the shift key, and the right Usually "<" key or ">" key.