Octal to Hex Converter

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Convert an octal number to hexadecimal. The two bases do not share a clean digit-to-digit mapping the way binary does, so the converter goes through the canonical decimal integer: 755 in octal is 493 in decimal and 1ed in hex. Useful when porting permission constants, embedded firmware values or legacy mainframe data into modern hex-based tooling. Choose lowercase or uppercase output for the hex side.

Octal (8)

Allowed: 0–7

Hexadecimal (16)

Allowed: 0–9, a–f

Octal (8) → Hexadecimal (16)

Quick reference table

Octal (8)Hexadecimal (16)
77
108
2010
10040
14464
377ff
7777fff

Glossary

Octal (base 8)

The octal numeral system uses digits 0 through 7. It was popular in early computing because each octal digit maps cleanly to exactly three binary digits, which made it convenient for systems with 12-, 24- or 36-bit words. Today its most common surviving use is Unix file permissions: chmod 755 means owner-rwx, group-rx, others-rx, where each digit is a 3-bit permission mask.

Hexadecimal (base 16)

The hexadecimal numeral system uses sixteen digits: 0–9 and a–f, where a–f represent 10–15. Each hex digit maps to exactly four binary digits (one nibble), which makes hex the compact human-readable form of binary data. Memory addresses, MAC addresses, MD5/SHA hashes, RGB color codes such as #ff8800 and machine-code bytes are all conventionally written in hex.

Related tools

Hex to Octal
Convert hexadecimal (base 16) to octal (base 8) — via canonical integer
Octal to Decimal
Convert octal numbers (base 8) to decimal — handy for Unix permissions
Octal to Binary
Convert octal (base 8) to binary — every digit expands to 3 bits
Number Base Converter
Convert integers between binary, octal, decimal and hexadecimal — with full BigInt support