What is it?
The Number Base Converter shows one number in binary (base 2), octal (8), decimal (10) and hexadecimal (16), plus Any base (2–36).
Who is it for?
Computer science students, programmers working with binary, hex and octal, electronics hobbyists, and anyone reading colour codes or file permissions.
How to use it
Type in any box; the others update. For another base, set it in Any base (2–36) and type in Number in that base.
Which digits are allowed?
- Binary: only 0 and 1. Octal: 0–7. Decimal: 0–9.
- Hex: 0–9 and A–F (capitals or small letters). Base 36 uses 0–9 and A–Z.
- A digit outside the base (like 2 in binary or G in hex) is not a valid number in that base.
Common uses
- Colours:
#FF8800is red 255, green 136, blue 0 in decimal. The Color Converter does this directly. - File permissions: chmod 755 is octal for rwxr-xr-x.
- Prefixes like
0x(hex),0b(binary) or0o(octal) in code are not part of the number. Leave them out.
Good to know
Group binary into fours to read it as hex: 1111 0101 is F5. Negative numbers in computers often use “two’s complement”, which depends on the bit width; this tool shows the plain value with a minus sign.
Errors and how to fix them
- “2” is not a digit in base 2. (or similar): a digit isn’t allowed in that base, like 2 in binary or G in hex. Remove it or choose the right box.
- Spaces or prefixes: leave out
0x,0band spaces between digit groups. - Long numbers: whole numbers of any length are converted exactly, so no digits are lost.
Open the tool: Number Base Converter
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.