Number base converter.

Type a number and see it in hex, decimal, binary, and octal at once — auto-detecting 0x, 0b, and 0o prefixes, with arbitrary-size integers (BigInt) for 64-bit IDs and bitmasks.

One value, four ways to read it

Backend work is full of the same number wearing different bases: file permissions in octal, byte and color values in hex, feature flags and permission sets as binary bitmasks, IDs in decimal. Converting in your head is error-prone, and normal JavaScript silently loses precision past 2^53 — right where 64-bit identifiers live. This shows every base at once and stays exact at any size, so you can read a value however the system in front of you expects it.