A number can be written using different sets of digits. Base 10 uses 0 through 9; base 2 uses only 0 and 1. Number Base Converter changes the writing, not the amount.
Turn 10 into binary
Set From base to 10 and To base to 2. Type 10 into Value. Result should be 1010. That is the same amount written using only zeros and ones.
Now replace Value with 255 and set To base to 16. You should see ff. In base 16, the letters a through f are digits after 9, so ff is the base-16 form of 255. You can type 0xff as input when From base is 16.
Swap exchanges the two base selectors; it does not replace your input with the last output. To convert back, also paste the earlier result into Value. For example, with base 16 → base 10, ff should become 255.
If a digit is rejected
The digit must exist in the starting base. 2 cannot be read as a base-2 digit. Check From base first, then your input. This tool handles whole numbers, including large ones; it does not convert fractions such as 0.5.
Where your input goes
Processing runs in your browser. The tool does not upload your input to ilham.dev.
Related guide
For more background, read Calculators and Unit Conversion.
Questions you might have
- Why does the value not change when I paste a very long number?
- Because it should not. This converter works on the digits rather than through a floating-point number, so a 64-bit value keeps every digit — which is the whole reason to use it instead of a calculator.
- How are values above 9 written in base 36?
- With the letters A–Z after the digits, so 35 is Z and 36 is 10.