About number base conversion
The same number can be written in different bases. Base 10 (decimal) is what we count in, but computers lean on base 2 (binary), base 8 (octal), and base 16 (hexadecimal). This tool converts a value between all four at once: type a number, tell it which base you typed, and it shows the other three instantly, in your browser.
What the bases are for
- Binary is the machine’s native language, just ones and zeros, mapping onto circuits that are on or off.
- Hexadecimal is binary made readable. Every hex digit stands for exactly four binary digits, so
ffis a tidy way to write11111111. That is why colors (#ff8800), memory addresses, and byte values are written in hex. - Octal groups binary into threes and shows up mainly in Unix file permissions, like
chmod 755. - Decimal is the human default.
Handling very large numbers
Simple converters break on big values, because the language’s normal number type loses precision past about 16 digits. This tool uses big-integer math instead, so it converts long values exactly, digit for digit, without rounding. Paste a 30-digit number and the hex you get back is correct.
If the input has a character that does not belong in the chosen base, like the digit 9 in a binary number or a stray letter, the tool flags it rather than guessing. Clear the bad character and the conversion updates the moment the value is valid.