A base converter lets you move a number between the counting systems computers and people use: binary (0 and 1), octal (base 8), decimal (everyday base 10) and hexadecimal (base 16).
Programmers use it constantly — reading memory addresses in hex, setting permission bits in octal, or checking how a number looks as bits in binary. It works fully offline and uses JavaScript BigInt, so even 60-digit numbers convert exactly.
Yes. Use a leading minus sign in decimal, e.g. -255, and it converts the magnitude across all bases with the sign preserved.
The output shows the plain digits. Add a 0x prefix when pasting into source code; the converter itself strips it on input.
No practical one. BigInt handles arbitrary precision, far beyond a normal 64-bit number.