Number Base Converter
Binary, octal, decimal and hex, all at once.
About Number Base Converter
Number Base Converter moves values between binary, octal, decimal and hexadecimal, showing all four at once, plus how many bits and bytes the value needs. Standard material in computer science courses, and useful for anyone reading colour codes, permissions or memory addresses.
How to use it
- Pick the base your number is in and type it. Invalid digits are flagged.
- All other bases appear immediately.
- The bits count shows how much storage the value needs.
Questions
Why does computing use hexadecimal?
Because one hex digit is exactly four bits, so a byte is always two hex digits. It is far more compact than binary while still mapping cleanly onto it.
What is the largest number this handles?
Up to 2⁵³, JavaScript’s safe integer limit. Beyond that it warns rather than silently losing precision.
Does it handle negative numbers or fractions?
No, positive whole numbers only. Two’s complement and floating-point representation are separate problems.
Number Base Converter is free and runs entirely in your browser. No account, no upload, no watermark, no limit on use.