~/devtools / number-base
tool::number-base

Number Base
Converter

Convert numbers between binary, octal, decimal, and hexadecimal in real time. Edit any field and all others update instantly.

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// about this tool

About Number Base Converter

A number base (or radix) determines how many unique digits are used to represent numbers. Decimal (base 10) uses 0–9 and is our everyday system. Binary (base 2) uses only 0 and 1 and is the native language of computers. Octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 plus A–F to represent values 10–15 in a single digit.

Hexadecimal is especially popular among developers because one byte (8 bits) maps exactly to two hex digits, making memory addresses, color codes, and checksums compact and readable. Octal is handy for Unix file permissions, where each digit encodes read, write, and execute bits for owner, group, and others — chmod 755 is a classic example.

This tool converts any integer — including negatives — across all four bases simultaneously. Type in any field and the other three update instantly. Copy buttons let you grab results with one click, and invalid input is flagged immediately so you never get a silent wrong answer.

Common Use Cases
  • ▸Convert decimal values to binary for bitwise operation debugging
  • ▸Translate hex color codes or memory addresses to decimal
  • ▸Verify octal file permission values (e.g. chmod 755) against binary representation
  • ▸Convert between bases when working on embedded systems or low-level code
  • ▸Quickly check hex opcodes or register values during reverse engineering
Frequently Asked Questions
Q. What do the hex digits A through F represent?
A=10, B=11, C=12, D=13, E=14, F=15. Hexadecimal needs 16 symbols per digit, so it extends 0–9 with A–F. Input is case-insensitive — both 'ff' and 'FF' are accepted.
Q. How do I enter a negative number?
Prefix any field with a minus sign (-). For example, entering -42 in decimal gives -101010 in binary, -52 in octal, and -2A in hex. Negative sign is supported in all four fields.
Q. Can I include prefixes like 0x or 0b?
No — enter the raw digits only, without any prefix. Binary accepts only 0 and 1; octal accepts 0–7; hex accepts 0–9 and A–F. The tool handles the conversion automatically.