What is BCD code?

BCD stands for Binary Coded Decimal. This code is useful for conversion of numbers into binary form. BCD numbers are Binary Coded Decimal numbers. In BCD, each decimal digit is represented by its equivalent four bit binary number.

For example, (23)₁₀  is represented by 0010 0011 using BCD, rather than (10111)₂. Observe that BCD  number requires more number of bits to code a decimal number. But it is very useful and convenient to write BCD numbers.

BCD numbers are very useful when decimal information is transferred into or out of the digital system. The circuits of pocket calculators, can process BCD numbers because you enter decimal numbers through keyboard and see decimal answers on LED or liquid crystal display. Digital clocks, digital voltmeters, electronic counters works with BCD numbers.

Decimal	Binary	BCD
0 9 10 15 255	0000 1001 1010 1111 1111 1111	0000 1001 0001 0000 0001 0101 0010 0101 0101

 Table shows BCD equivalent for decimal numbers.