Binary to Decimal Converter
Convert binary to decimal, plus hexadecimal and octal. Exact big-integer conversion that handles very long binary numbers without rounding.
Independently verified for accuracy
Calculator by Toolsloft ↗- Decimal
- 255
- Hexadecimal
- ff
- Octal
- 377
Convert a binary number to decimal, and also see it in hexadecimal and octal. Paste a string of 0s and 1s and get the base-10 value instantly. It uses exact big-integer math, so even very long binary numbers convert without rounding.
How this is calculated
The binary string is read as a base-2 integer using arbitrary-precision arithmetic, which is the standard positional-notation conversion where each digit is worth twice the one to its right. The same value is then written in base 10, base 16, and base 8. A leading minus sign is preserved and non-binary input is rejected.
How to use
- Type or paste a binary number (only 0s and 1s).
- Read the decimal value, along with the hex and octal forms.
- Copy whichever result you need.
Examples
- One byte:
11111111 → 255 - Small value:
1010 → 10
FAQ
- How large a binary number can it convert?
- There is no practical limit. The conversion uses arbitrary-precision integers, so a binary string of hundreds of digits converts to its exact decimal value with no rounding or overflow.
- Does it handle negative numbers?
- Yes. A leading minus sign is treated as a sign, so -110 converts to -6. This is signed magnitude, not two-complement encoding.
- What if I enter a character that is not 0 or 1?
- The tool rejects the input and asks for a valid binary number instead of guessing. Only 0s and 1s, with an optional leading + or - sign, are accepted.