(Binary Coded Decimal) The storage of numbers in which each decimal digit is converted into binary and is stored in a single character or byte. For example, a 12-digit number would take 12 bytes. See binary numbers.
BCD and Binary
The BCD method codes each decimal digit in binary and stores it in its own byte. The binary method converts the entire decimal number into a binary number. In the binary example above, the 1 in the left byte is the ninth bit starting from the rightmost bit in the right byte (256-128-64-32-16-8-4-2-1-0).
How Numbers Are Stored
BCD is one of four primary ways numbers are stored in the computer.