Number Base Converter
Binary, octal, decimal, hex — plus bit operations
Input
Result
- Binary
1111 1111 - Octal
377 - Decimal
255 - Hexadecimal
FF
Bit details
Positive shifts left (<<), negative shifts right (>>).
<< 0 = 255 (0xFF)
Supports values up to the range JavaScript represents exactly (about 9 quadrillion).
Colour codes are hex, permissions are octal, flags are binary, and people are decimal. Type a value in any base and see it in all four at once, along with the bit-level details that usually prompted the question.
How to use
- 1 Choose the base of the value you are entering.
- 2 Type the value — all the other bases update at once.
- 3 Check the bit length and how many bits are set.
- 4 Use the shift control to see the effect of << and >>.
Frequently asked questions
Why is hexadecimal used so much in computing?
One hex digit is exactly four bits, so a byte is always two hex digits. That makes the mapping between hex and the underlying bits obvious in a way decimal never is.
What does the shift operation do?
Shifting left by one doubles the value, shifting right halves it and discards the remainder. It appears constantly in bit flags, hashing and low-level graphics code.
Why do very large numbers lose precision?
JavaScript numbers are 64-bit floats and are exact only up to about 9 quadrillion. Beyond that the low bits are approximated, so this tool stops at that boundary rather than showing wrong answers.