How to use
- Type or paste your number into the value box (an optional leading + or - sign is allowed).
- Select the base your number is written in: binary (base 2), octal (base 8), decimal (base 10) or hexadecimal (base 16).
- Read the converted result live in all four bases displayed below.
- Copy any output value straight from its field to reuse in your code or documents.
Frequently asked questions
Which number bases does this converter support?
It supports binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16). Whatever base you pick for your input, the value is shown in all four bases at the same time.
Are my numbers uploaded or stored anywhere?
No. The entire conversion happens locally in your browser, so nothing is ever sent to a server or saved. Your numbers stay 100% private.
Can it handle very large numbers?
Yes. Conversion uses BigInt internally, so even extremely large integers — well beyond the usual 32-bit or 64-bit limits — convert exactly with no rounding or loss of precision.
Does it support negative numbers?
Yes. You can start your value with a - sign for negative numbers or an optional + sign, and the result keeps the correct sign across binary, octal, decimal and hex.
Can it convert decimals or fractions like 3.14?
No. This tool works with whole integers only. Decimal points, fractions and floating-point values are not supported, so remove any dot before converting.
What happens if I enter an invalid value?
If your input contains characters that are not valid for the selected base — such as a 2 in binary or a G in hex — the outputs clear and an 'invalid number' message appears until you fix it.
About this tool
Free number base converter: convert integers between binary, octal, decimal and hex instantly. Runs 100% in your browser with no uploads — your data stays private.