Binary-Coded Decimal

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What Does Binary-Coded Decimal Mean?

A binary-coded decimal (BCD) is a type of binary representation for decimal values where each digit is represented by a fixed number of binary bits, usually between four and eight.

The norm is four bits, which effectively represent decimal values 0 to 9. This writing format system is used because there is no limit to the size of a number. Four bits can simply be added as another decimal digit, versus real binary representation, which is limited to the usual powers of two, such as 16, 32 or 64 bits.

Techopedia Explains Binary-Coded Decimal

Binary-coded decimals are an easy way to represent decimal values, as each digit is represented by its own 4-bit binary sequence which only has 10 different combinations. By comparison, converting real binary representation to decimal requires arithmetic operations like multiplication and addition.

It is easier for conversion to decimal digits for display or printing, but the resulting circuit required to implement this system is more complex.For example, the binary coded decimal “1001 0101 0110,” which has three groups of 4 bits, means there are three decimal digits. In order, from left to right, the resulting decimal value is 956.

The following are the 4-bit binary representation of decimal values:

0 = 0000
1 = 0001
2 = 0010
3 = 0011
4 = 0100
5 = 0101
6 = 0110
7 = 0111
8 = 1000
9 = 1001

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.

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