The highest decimal value a byte can represent is 255.

Quick Scoop

A byte has 8 bits, and each bit can be either 0 or 1, so the largest possible binary pattern is 11111111₂.

This pattern corresponds to 28−1=2552^8-1=25528−1=255 in decimal, which is why 255 is the maximum value for a single 8-bit byte in unsigned representation.

Why 255 and not 256?

  • With 8 bits, there are 28=2562^8=25628=256 different combinations.
  • Because counting starts at 0, the values run from 0 to 255, giving 256 total distinct values.

Mini note on signed vs unsigned

  • For unsigned bytes: range is 0 to 255, so the highest value is 255.
  • For signed 8-bit values (like two’s complement), the range is typically from −128 to 127, so in that case the highest positive value is 127, but the byte still physically stores up to 255 distinct patterns.

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Learn what the highest decimal value a byte can represent is, why it’s 255 and not 256, and how this relates to signed and unsigned 8-bit values in computing.

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