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Octal to Hex
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Decimal · base 10
Hexadecimal · base 16
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Binary · base 2
Octal · base 8
Enter a octal value above to convert it
// about this tool

Octal to Hex Online

Updated 2026-10-24

Convert octal to hexadecimal online for free. Paste an octal value and SnapTools shows its hexadecimal representation instantly, right in your browser. Nothing you enter is uploaded.

Octal shows up most often today in Unix and Linux file permissions (chmod 755, 644) and in older C and POSIX code that still uses base-8 literals. Hex is what most modern tooling (debuggers, bitmask constants, config files) actually expects, so this converter bridges the two directly instead of making you go through binary by hand. For every base at once, use the Number Base Converter.

// how to use

  1. 1 Paste or type an octal (base-8) value into the input, using digits 0-7 only.
  2. 2 SnapTools converts it to hexadecimal as you type.
  3. 3 Copy the hex result, or open the Number Base Converter for all bases at once.

// examples

Common file permission
Input
755
Output
1ED
Byte value
Input
377
Output
FF

// common uses

Converting Unix file-permission values (chmod 755, 644) into hex bitmasks Reading legacy octal literals from C, POSIX tools, or old file formats Checking a manual octal-to-hex conversion Learning how base-8 and base-16 relate to binary

// faq

Why does octal not divide evenly into modern 32-bit or 64-bit values the way hex does?
A 32-bit or 64-bit value splits perfectly into 8 or 16 hex digits because those widths are multiples of 4, but 32 is not a multiple of 3, so the leading octal digit of a full-width value only ever covers 2 bits instead of 3. That mismatch is a real reason modern tooling defaults to hex rather than octal for anything wider than a Unix permission triplet.
How do I convert octal to hex by hand?
Convert the octal value to binary first (each octal digit is exactly 3 bits), then regroup those bits into 4-bit nibbles and read off the hex digits. This tool skips the manual regrouping and gives you the answer directly.
Why does chmod 755 show up in the examples?
Unix/Linux file permissions are traditionally written in octal (owner/group/other, each 0-7). Converting a permission value like 755 to hex is a common need when working with permission bitmasks in C, Python, or low-level tooling that expects hex.
Does it accept a leading 0 (like old-style octal literals)?
Yes. An old-style leading zero does not change the value in octal, so the converter treats it as a non-significant digit and there is no need to remove it beforehand.
What if my input has an 8 or 9 in it?
Octal digits stop at 7; there is no 8 or 9 in this base, so either one showing up in the input gets rejected immediately rather than silently turned into a bogus hex value.

// works with your data

Hex to Octal Octal to Binary Octal to Decimal Number Base Converter Hex to Binary SHA-256 Hash Generator

Use this via API

Get a free API key → 
curl -X POST https://thesnaptools.com/api/v1/tools/octal-to-hex \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"number":"755"}'