How to Convert and Calculate Number Bases

Step-by-step

1. Identify the source base of your number.
2. Check that each digit is valid for that base.
3. Enter the value and select the target base.
4. Convert the value and review the output.
5. If accuracy is important, convert the result back to the original base and compare it with the input.

Common number bases

Decimal uses base 10, binary uses base 2, octal uses base 8, and hexadecimal uses base 16. Each system represents values with its own place-value rules.

Why conversions fail

A digit that is valid in one base may be invalid in another. For example, 2 is not a valid digit in a binary number. Always select the correct source base before converting.

Worked example

The decimal number 255 is FF in hexadecimal, 377 in octal and 11111111 in binary. Enter 255 with From base 10 and the tool shows all of them.