Octal groups binary digits in threes, so each octal digit stands for exactly 3 bits. It is still used for Unix file permissions, where 111 101 101 is chmod 755.
How to use the Binary to Octal Converter
- Number
- Input base
- Convert to
- Two’s complement width
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How it works
The number is read exactly using arbitrary-precision integers (so very long values are not rounded), then written in each base. Two’s complement shows how a negative number is stored in the chosen number of bits.
Formula
value = Σ digit × base^positionTo convert: divide repeatedly by the new base and read the remainders in reverse.Worked example
Inputs — Number: 111101101; Input base: Binary (2); Convert to: Octal (8); Two’s complement width: No fixed width.
Results — Result = 755; Binary = 1 1110 1101; Octal = 755; Decimal = 493; Hexadecimal = 1ED; Bits needed = 9.
Key terms
- Bit
- A binary digit, 0 or 1.
- Nibble
- Four bits, one hexadecimal digit.
- Two’s complement
- The standard way computers store negative integers.
Frequently asked questions
What is 255 in binary?
1111 1111.
What is FF in decimal?
255.
How do I convert binary to hex by hand?
Split the bits into groups of four from the right and replace each group with its hex digit (0000 = 0 … 1111 = F).
What formula does the Binary to Octal Converter use?
value = Σ digit × base^position.