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Number bases

Converting between decimal, binary, octal and hexadecimal.

A base-b number is a sum of powers of b. To convert from decimal, divide by b repeatedly; the remainders, read from the last to the first, are the digits. Binary (base 2) and hexadecimal (base 16) are how computers store every number you see.

Worked example: 255 to binary

Number-Theory · Number-Bases

255 to binary

255,\ 2

Step by step

  1. 255_{10} \to \text{base } 2

    Repeatedly divide by 2; the remainders, read bottom-up, are the digits.

  2. 255 = 127 \times 2 + 1

    remainder 1

  3. 127 = 63 \times 2 + 1

    remainder 1

  4. 63 = 31 \times 2 + 1

    remainder 1

  5. 31 = 15 \times 2 + 1

    remainder 1

  6. 15 = 7 \times 2 + 1

    remainder 1

  7. 7 = 3 \times 2 + 1

    remainder 1

  8. 3 = 1 \times 2 + 1

    remainder 1

  9. 1 = 0 \times 2 + 1

    remainder 1

Reveal the answer
255_{10} = 11111111_{2}

Try your own

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