Number Bases

Base converter

Exact unsigned-integer conversion from any input base 2–36 to common or custom output bases.

Input number

From base

Custom base (2–36)

Result in custom base

Exact Integer Arithmetic

This converter uses JavaScript's native BigInt type, so conversions stay exact for arbitrarily large integers — no floating-point rounding, even at base 36.

Bases 2–36

Digits beyond 9 use letters A–Z, so base 36 is the practical ceiling — every digit of the Latin alphabet plus 0–9 is used exactly once.