Binary to Decimal Converter
Read binary as a decimal number, either as a plain unsigned value or as a signed two’s complement integer.
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What is Binary to Decimal Converter?
Each binary digit is worth a power of two, starting from the right: 1010 is 8 + 2 = 10. This tool sums those powers with big-integer arithmetic, so 200-bit or 2,000-bit inputs are exact.
It ignores spaces, underscores and a leading 0b, so pasted patterns such as 1111 1011 work. Choose a signed interpretation to read the top bit as the sign: 11111011 is 251 unsigned but −5 as a signed 8-bit value. A thousands separator can make long results easier to read.
How does it work?
- Paste one binary number per line; separators and the 0b prefix are ignored.
- Keep “Unsigned” for a normal value, or pick a signed width (8, 16, 32, 64) for two’s complement.
- Optionally pick a thousands separator for the decimal output.
- Copy the results; rows for a single number also show hex and octal.
Common use cases
- Decoding a bit field or flag register value copied from a debugger.
- Reading a raw signed byte or word from a hex dump as its real negative value.
- Converting long binary strings from logic-design or networking exercises.
- Checking manual binary arithmetic.
Examples
Try this input in the tool above:
1010 0b11111111 1111 1011
10 255 251
Privacy
Binary to Decimal Converter runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.
Limitations
A signed interpretation needs the bit pattern to fit the chosen width. Shorter inputs are zero-extended, so 1 in signed 8-bit is 1, not −1. Only 0 and 1 are valid digits; use the Base Converter for other bases.
Frequently asked questions
Why do I get a negative number?
You chose a signed width and the leading bit of the padded pattern is 1. In two’s complement that bit carries a negative weight, so 11111011 is −5 in 8 bits.
Does it accept spaces between groups of bits?
Yes. Spaces, underscores and a 0b prefix are removed before conversion, so 1111 0000 is read as 11110000.
Can it convert a very long binary string?
Yes. Conversion uses arbitrary-precision integers, so the result is exact for thousands of bits.
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