Use the Number Base Converter in three steps
Choose the input base
Tell the converter how the current digits should be interpreted.
Enter the integer
Use only digits valid for that base, with an optional minus sign.
Copy a representation
Use the binary, octal, decimal, or uppercase hexadecimal result.
Each base has its own valid digits
Binary uses 0–1, octal 0–7, decimal 0–9, and hexadecimal 0–9 plus A–F. Invalid digits are rejected instead of silently changing the number.
Integer conversion remains exact
The implementation uses BigInt rather than floating-point numbers, so very large whole numbers do not lose low-order digits.
Number Base Converter FAQ
Can I enter lowercase hexadecimal?＋
Yes. Uppercase and lowercase A–F are both accepted.
Are negative numbers supported?＋
Yes. Put a minus sign before the digits.
Can I convert fractions?＋
No. This tool is designed for whole integers only.
Why is a digit rejected?＋
It is not valid in the selected input base, such as 2 in binary or 9 in octal.
Are prefixes such as 0x required?＋
No. Choose the base from the list and enter only the digits.
Will large values be rounded?＋
No. BigInt conversion keeps integer values exact.