'''4-bit computing''' refersis tothe use of [[computer architecture]]s in which [[integer (computer science)|integers]] and other [[data (computer science)|data]] units are 4 [[bit]]s wide. 4-bit [[central processing unit]] (CPU) and [[arithmetic logic unit]] (ALU) architectures are those that are based on [[processor register|registers]] or [[Bus (computing)|data buses]] of that size. [[Memory address]]es (and thus [[address bus]]es) for 4-bit CPUs are generally much larger than 4-bit (since only 16 memory locations would be very restrictive), such as 12-bit or more, while they could in theory be 8-bit.
A group of four bits is also called a [[nibble]] and has 2<sup>4</sup> = 16 possible values.
