TontonTools

Octal to HEX

Convert octal to hexadecimal — chmod-style values into byte notation.

100% Free No signup Privacy-friendly Binary & Number Tools
Updated Sep 2026

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How to use Octal to HEX

  1. Enter the octal value — e.g. 755 (digits 0–7 only).
  2. Read the hex instantly: 755 → 1ED.
  3. Watch the error line — an 8 or 9 anywhere in the input is named as invalid.
  4. Click “Copy result” — add 0x in front for most programming languages.

What is Octal to HEX?

An octal to hex converter translates base-8 values into base 16. Octal 755 is hex 1ED; octal 377 is hex FF. Because octal digits are 3 bits and hex digits are 4, the conversion works by expanding to binary and regrouping — 755 → 111 101 101 → 1 1110 1101 → 1ED — which is exactly the fiddly step this tool automates.

Practically, this is the modernization direction: octal is the legacy notation (permissions, old escape sequences), and hex is what today's debuggers, editors and specs display. Moving a value from chmod-land into byte-land is an octal → hex conversion.

About the Octal to HEX

Enter an octal value — digits 0–7 — and its hex form appears instantly, exact at any length.

Typical cases: expressing a Unix file mode as the hex constant an API wants (755 → 0x1ED), converting octal escape values from old C strings or core dumps into the hex a modern hex editor shows (\377 → 0xFF), and completing homework tables that ask for a value in all four bases. Digits 8 and 9 are flagged as invalid immediately, since they don't exist in base 8.

All conversion runs in your browser. Hex to Octal covers the reverse; Octal to Binary lets you see the 3-bit expansion that powers the regrouping.

Frequently Asked Questions

1ED. Expand to binary (111 101 101), regroup in fours from the right (1 1110 1101), read as hex: 1, E, D. This tool does the regrouping instantly.
FF — both are decimal 255, the full byte. Legacy code says \377 where modern code says 0xFF; they are the same value in different eras' notation.
Because 3-bit and 4-bit groups only align every 12 bits. There is no per-digit lookup between them — binary is the necessary middle step, unlike hex↔binary or octal↔binary.
Languages and tools that print all integers in hex (debuggers, some Windows APIs, protocol dumps) will show mode 755 as 0x1ED. Recognizing the pair saves confusion in cross-platform code.
Yes — separate them with spaces and each converts independently, keeping results aligned with inputs. Handy for a table of permission modes or escape values.

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