0xFF Is 255. But What’s It in Binary? And Octal?
If you’re debugging a memory dump, setting Unix file permissions, working with bit flags, or just trying to figure out what a hex color code looks like in decimal — you’re doing number base conversions. It’s one of those things that comes up constantly in programming and computer science, and doing it by hand gets old fast.
The Number System Converter takes a number in any base from 2 to 36 and shows you its representation in binary, octal, decimal, hexadecimal, base 32, base 36, and any custom base you want. Enter decimal 255, and you’ll see binary 11111111, octal 377, and hex FF all at once. Enter hex 1A3F, and you’ll get decimal 6719, binary 1101000111111, and octal 15077.
One tool, all bases, one-click copy for every result. Everything runs in your browser.
What’s Covered
- Binary (base 2), octal (base 8), decimal (base 10), hexadecimal (base 16) — the standards
- Base 32 and base 36 for encoding schemes and compact representations
- Custom base support for anything from 2 to 36
- Negative number support with minus prefix
- Instant results and one-click copy for each output
How to Use It
- Select the input base
- Enter your number
- See every standard base (binary, octal, decimal, hex) update at once as you type, no button to press
- Set a custom output base if you need something specific
Where Each Base Shows Up
Binary is everywhere in digital circuits, bitwise operations, and low-level programming. Octal shows up in Unix file permissions — chmod 755 is octal for specific permission bits. Decimal is what humans naturally read. Hexadecimal is the workhorse of programming: memory addresses, color codes (#FF5733), byte values, MAC addresses. Base 32 appears in encoding schemes like Crockford’s base32 and some distributed system identifiers. Base 36 packs the maximum amount of information into alphanumeric characters (0-9 plus A-Z).
Practical Scenarios
- Debugging — you’re staring at a hex memory address and need to understand the binary bit pattern it represents
- Setting Unix permissions and needing to know what octal 644 means in binary
- Networking — converting MAC addresses between hex and decimal for protocol analysis
- CS students practicing base conversion problems for exams (it’s faster to verify your manual work with a tool than to second-guess yourself)
- Web development where you’re converting between hex color codes and RGB decimal values
For color-specific conversions that include HSL and CMYK, the Color Format Converter Pro is more appropriate. The Unit Converter Pro handles measurement unit conversions across 12 categories.
Quick Answers
What digits does it use for bases above 10?
Letters A through Z represent values 10 through 35. Hexadecimal uses 0-9 and A-F. Base 36 uses the full set: 0-9 and A-Z.
Does it handle negative numbers?
Yes. Prefix with a minus sign and the tool converts the absolute value while preserving the negative sign across all outputs.
Is any data sent to a server?
No. All math happens in your browser. Nothing leaves your device.
Free to use?
Yes, completely. No accounts, no limits.