Bit numbering

The bit significance refers to the value of a single bit, which it has by its position (also known as a binary number ) in a binary number. It is important to this definition, among others in serial data transmission as well as for parallel buses in data processing.

Eight bits grouped into bytes and these in turn to larger number formats, so the byte order is to be defined, this little-and big -endian format can be distinguished.


The most significant bit is the bit which is within the number of the point with the highest priority. With a binary number that is the one - digit bit is the most significant bit, which is at the -th digit ( multiplication ). Often the abbreviation MSB is used (from the English for most significant bit) for the most significant bit.


Analogous to the MSB, the LSB has the lowest value ( multiplied by ). In English, the abbreviation LSB (English for least significant bit ) is used for the least significant bit.

Bit order

If you imagine a sequence of bits horizontally in front, so it depends on the bit order, whether with the bit count right ( with the LSB ) or left ( with the MSB ) is started.

Starts the count to 0 for the least significant bit (LSB ) on the right side and goes from right to left, it is called "LSB 0". The other hand, start counting with 0 the most significant bit (MSB ) on the left and from left to right, then one speaks of "MSB 0".

Number format and sign

The most significant bit (MSB) is in one's complement, twos complement number, and other formats with the sign bit and indicates whether the corresponding decimal number is positive (MSB 0 ) or negative ( MSB 1). When two's complement zero counts to the positive numbers, so you can represent more negative than positive numbers. For different number formats like the one's complement or floating-point IEEE -754 standard, there are two representations of zero ( 0 and -0 )

Bits and bytes

Analogous to the most significant bit MSB also called the "most significant byte" (MSB, most significant byte ); analogous to LSB and the " least significant byte " (LSB, least significant byte ). Since both terms with MSB or LSB be abbreviated, if necessary, must be recognized from the context of the requirements which version of the confusion is meant there is a cause for problems.

  • Assembler
  • Number system
  • Computer arithmetic