Choose bases 2–36
The digit alphabet is 0–9 then a–z. A digit is valid only when its numeric value is lower than the selected source base.
Any integer · no rounding
Change the base, not the integer.
Choose source and target bases from 2 through 36, enter a complete signed integer, and convert locally with exact BigInt accumulation. NumberBase validates every character before calculation and shows the same mathematical value in bases 2, 8, 10, 16, and 36—without fractions, exponents, text encoding, or hidden Number rounding.
No parseInt, floating point, backend, storage, history, text encoding, or indexed custom result.
Three exact steps
Select, validate, convert
Validate the whole string
NumberBase accepts one optional leading minus and integer digits only. It rejects a bad character anywhere instead of partially parsing a prefix.
Accumulate with BigInt
For every digit, value = value × source base + digit. The exact signed BigInt is then rendered in the target base without passing through Number.
Nine focused converters
Use the route that matches the conversion
- Convert any exact signed integer between arbitrary bases 2 through 36.
- Use dedicated binary↔decimal, hexadecimal↔decimal, binary↔hex, and octal↔decimal paths.
- Inspect sixteen curated boundary values in bases 2, 8, 10, 16, and 36.
- Keep negative values as sign plus magnitude; NumberBase does not infer a two's-complement width.
Use your own integer
Keep every digit exact
Choose bases 2–36 and convert locally with complete validation and exact BigInt arithmetic. Inputs and outputs never become public result URLs.