Number Base Converter

Accepted input

• Prefixes 0x, 0b and 0o switch the base automatically.
• Underscores, spaces and commas are ignored, so 1_000_000 and ff ff work.
• A leading minus sign makes the number negative.

Two's complement

Computers store negative integers in two's complement: the bit pattern of -1 in 8 bits is 11111111 (0xFF). The table shows that pattern for the width you choose, and for a hex or binary input it also shows the signed value of that bit pattern, which helps when reading register dumps or packet captures.

FAQ

Is there a size limit?

No practical one. The tool uses JavaScript BigInt, so 256-bit values such as Ethereum token amounts convert exactly.

Does it handle fractions?

No, only integers. Fractional values in other bases are rarely what developers need and are easy to get wrong.