Binary is the base-2 positional numeral system. It represents numbers using two symbols: 0 and 1.

Computers use binary in digital circuitry using logic gates, where the symbols translate to states of off (0) and on (1).

Here are binary numbers corresponding to 0 to 10 in the decimal system:

Decimal   Binary
-------   ------
      0        0
      1        1
      2       10
      3       11
      4      100
      5      101
      6      110
      7      111
      8     1000
      9     1001
     10     1010

Other tags

• Compiled computer programs are sometimes called "binaries". Instead of this tag, use executable for this sense.
• math
• binary is made up of bits, 4 bits is called a nibble and 8 bits is called a byte
• Other numeral systems: binary (base 2), ternary (base 3), octal (base 8), decimal (base 10), hexadecimal/hexadecimal-notation (base 16)