Octal to Hexadecimal Converter
Octal to hex for values copied out of chmod modes or old configs. Enter one per line, 0o prefix optional, and the hex comes back uppercase: 755 is 1ED.
Input
Output
What Is Octal to Hexadecimal Conversion?
Octal to hexadecimal conversion transforms numbers from the base-8 (octal) numeral system into the base-16 (hexadecimal) numeral system. Both are positional numeral systems defined by their radix (number base). Octal uses digits 0-7, while hexadecimal uses digits 0-9 and letters A-F to represent values.
Both octal and hexadecimal are commonly used in computing. Hexadecimal is widely used for memory addresses, color codes, and low-level programming, while octal is used in Unix file permissions and some legacy systems. For a detailed mathematical treatment of hexadecimal, see Wolfram MathWorld. Paste octal integers here and their hexadecimal values appear straight away.
How to Use This Tool
Enter Octal Numbers
Enter octal values on the left, one per line, the way you would copy them out of an ls -l permissions column or a legacy config. Sample fills in a few to try, and Upload reads a text file of them.
View Hexadecimal Output
The right panel updates automatically with the hexadecimal representation of each octal number. The output uses uppercase letters (A-F).
Copy or Download
Those hex results go to your clipboard with Copy, or keep it as a plain text file via Download.
Conversion Examples
Here are some common octal to hexadecimal conversions:
Octal Input
Hexadecimal Output
Frequently Asked Questions
How does octal to hexadecimal conversion work?
The conversion works by first converting the octal number to its decimal (base-10) equivalent, and then converting that decimal value to hexadecimal. For example, octal 377 equals decimal 255, which equals hexadecimal FF. You can practice this at Math is Fun.
Does this tool support the 0o prefix?
Yes. The tool automatically strips the 0o prefix before converting. You can enter values like 0o377 or just 377.
Do my numbers get sent anywhere?
No. The base-8 to base-16 arithmetic is done by your own browser, and the values you type stay on your machine.
Does it support negative numbers?
Yes. Negative octal numbers produce a hexadecimal result prefixed with a minus sign (e.g., -377 becomes -FF). You can also try CalculatorSoup's octal-to-hex converter to cross-check results.
Related Tools
Learn more: Khan Academy digital information course, Cisco hex guide for networking, and the Wikipedia article on octal.