What are the benefits of BCD code

BCD code

The BCD code, Binary Code Decimal (BCD), also known as 8-4-2-1 code, is used for the binary coding of decimal numbers. When coding, each decimal digit is individually dual-coded. The BCD code encodes four bits. This corresponds to 16 different values ​​to which letters or numbers can be assigned. Bit groups of four bits are also referred to as a tetrad, nibble or half-byte.


The BCD code assigns the digits 0 to 9 to the first ten values. No letters are assigned to the other 6 valencies, as is the case with the hexadecimal system, where these have the letters A to F. In the place value system of the BCD code, the remaining six values ​​are referred to as pseudotetrads and they are sometimes assigned carries or mathematical symbols.

A four-digit dual number combination is assigned to a single decimal number in the BCD code. As far as the value is concerned, the binary number on the left has the highest value and is the Most Significant Bit (MSB). The right dual number has the lowest valence. It represents the Least Significant Bit (LSB).

If a multi-digit decimal number is shown in BCD code, then each individual digit is dual-coded. The conversion of the number 418 results in the binary number 0100 0001 1000. By shifting the pseudotetrad, the Aiken code and the excess 3 code were derived from the BCD code, which can also be assigned to the BCD codes. These codes work with an offset compared to the BCD code, which can be used to advantage in some mathematical operations. Other codes derived from the BCD code are the BCDIC code, Binary Coded Decimal Interchange Code (BCDIC) and the EBCDIC code, Extended Binary Coded Decimal Interchange Code (EBCDIC).

The BCD system is still used in numerical display modules, also for time signals or when sending short messages.