Number Base Converter
Type a number in binary, octal, decimal or hexadecimal and watch all four bases update live — free and private.
Programmers, students and electronics hobbyists constantly switch between number bases, and this converter makes it effortless. Type into any of the four fields — binary, octal, decimal or hexadecimal — and the other three recalculate instantly with validation. It is perfect for homework, bit manipulation and reading memory addresses.
Type a number in any base — the other three update automatically.
How to use the Number Base Converter
- Type a number into any one of the four base fields.
- The other three fields update automatically as you type.
- If the digits are invalid for that base, a hint appears — fix the input to continue.
Number Base Converter — FAQs
Why do programmers use hexadecimal?
Hexadecimal is compact shorthand for binary: each hex digit represents exactly four bits, so a byte fits in two hex characters. Memory addresses, color codes like #FF5733 and machine-code dumps are all written in hex because it is far more readable than long binary strings.
Can I enter negative decimal numbers?
Yes, the decimal field accepts a leading minus sign and the other bases show the magnitude converted. Note that computers usually represent negatives with two's complement, which this educational converter does not apply — it converts the absolute value and keeps the sign only on the decimal side.
What does the invalid digits warning mean?
Each base allows only certain digits: binary accepts 0 and 1, octal accepts 0–7, decimal accepts 0–9, and hexadecimal adds A–F. If you type a digit outside that range, the tool warns you instead of guessing, so a binary input of 102 is flagged immediately.
Is my data uploaded anywhere?
Your data never leaves your device. This converter runs entirely in your browser using JavaScript, so nothing is uploaded, stored, shared or tracked. It works offline too, and you can use it as often as you like with complete confidence.