Binary, Decimal & Hex Converter
Convert a signed whole number between binary, octal, decimal, and hexadecimal with exact integer arithmetic.
Your result
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Choose Calculate to see your result.
How to use this calculator
- Enter your values in the labeled fields, keeping the displayed units.
- Choose Calculate or press Enter in a single-line field.
- Review the result and the assumptions below before using it.
Formula and method
A positional number equals the sum of each digit multiplied by a power of its base. The same integer can be written in different bases.
Worked example
Decimal 255 equals binary 11111111, octal 377, and hexadecimal FF.
What the result assumes
Enter up to 256 digits without 0x or 0b prefixes. Negative values use a minus sign rather than a fixed-width two’s-complement representation.
Common question
Does it convert fractional numbers?
No. This converter handles whole numbers exactly, including integers beyond the standard floating-point safe range.