Base Converter
Last updated: 2026-06-25
The base converter is a free tool that converts between binary, octal, decimal and hexadecimal, showing the remaining bases at once from a single value.
It handles large numbers exactly with BigInt, and every conversion runs in your browser.
Base conversion
| Base | Value | |
|---|---|---|
| Binary | | |
| Octal | | |
| Decimal | | |
| Hex | |
How to use
- Choose the input base — select the base of the value you will enter (binary, octal, decimal or hex).
- Enter a value — enter a value in that base (e.g. ff for hexadecimal).
- Review the result — click Convert to show the binary, octal, decimal and hex results in a table at once.
Understanding number bases (radix)
A base (radix) is the number of digits used to represent numbers. People use decimal, but computers work in binary (only 0 and 1), and memory addresses, colors and hashes are often written in compact hexadecimal.
| Base | Digits used | 255 written |
|---|---|---|
| Binary | 0–1 | 11111111 |
| Octal | 0–7 | 377 |
| Decimal | 0–9 | 255 |
| Hex | 0–9, a–f | ff |
Hexadecimal is also used in color codes (#ff0000). For color conversion, use the color converter; to work with Unix time values, use the timestamp converter.
Frequently asked questions (FAQ)
Which bases can I convert?
It converts between binary, octal, decimal and hexadecimal. Enter a value in one base and it shows the other three bases at once.
Are negatives and decimals supported?
This tool converts non-negative integers. Negative signs and decimal points are not supported, and invalid characters show an error. Even very large numbers are handled exactly with BigInt.
Does letter case matter for hex?
Input is recognized in either case (ff equals FF). The hexadecimal result is shown in lowercase.
Are large numbers converted accurately?
Yes. This tool uses JavaScript BigInt to convert very large numbers beyond the normal integer range without rounding errors.
Related tools & guides
Last updated: 2026-06-25