Binary / Hex / Decimal Converter
Convert a number between binary, octal, decimal and hexadecimal.
Decimal
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Binary
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Hexadecimal
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Octal
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Bit length
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Results update as you type.
About this calculator
This converter takes a whole number in binary (base 2), octal (base 8), decimal (base 10) or hexadecimal (base 16) and shows it in all four bases at once. It is handy for programming, bit masks, colour codes and low-level debugging.
Frequently asked questions
How do I convert decimal to hexadecimal?
Repeatedly divide by 16 and read the remainders from last to first, using A–F for 10–15. Decimal 255 is FF in hex and 11111111 in binary.
Why is hexadecimal used in computing?
Each hex digit maps to exactly four binary bits, so hex is a compact, readable way to write byte values and memory addresses — 0xFF is one byte of all ones.
Results are estimates for general guidance only, not financial, medical or tax advice.