Converters
Binary Converter
Convert between binary, decimal, hexadecimal and octal — handles huge numbers exactly.
That is not a valid number in the selected base.
Decimal
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Binary
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Hexadecimal
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Octal
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About this tool
Convert any number between decimal, binary, hexadecimal and octal in one view. Enter a value in any base and instantly see it in all four — the everyday translation task of CS students, embedded developers and anyone reading bitmasks or color codes.
It uses exact big-integer math, so numbers far beyond the usual 53-bit JavaScript limit convert without losing digits.
How to use
- Type your number and select which base it is in.
- Read the value in decimal, binary, hex and octal simultaneously.
Frequently asked questions
11111111 in binary and FF in hex — one full byte, which is why hex pairs map so neatly onto bytes.
One hex digit represents exactly 4 bits, so a byte is always two hex digits — far more compact and readable than binary.
Yes — 0x, 0b and 0o prefixes are stripped automatically, as are spaces and commas.