Convert octal whole numbers to hexadecimal exactly, or switch directions to decode hexadecimal values back to octal.
Last updated: August 2026 | By Workshelve Team
Octal uses eight digit values and hexadecimal uses sixteen. The converter preserves the integer while rewriting it in base 16.
Each octal digit maps to three binary bits. Regrouping those bits into sets of four produces hexadecimal digits.
Octal still appears in technical contexts such as Unix-style permission notation, while hexadecimal is common for compact binary-oriented values.
Octal is base 8, so every digit is from 0 through 7. Hexadecimal is base 16 and extends 0–9 with A–F. Because both bases are powers of two, binary gives a clean way to move between them.
Replace each octal digit with three binary bits. Join the groups, then regroup the bit string into four-bit sets starting from the right. Add leading zeros to the leftmost group if needed. Each four-bit group becomes one hexadecimal digit.
For example, 731₈ becomes 111 011 001₂. Regrouping as 0001 1101 1001 gives hexadecimal digits 1, D, and 9. Therefore 731₈ = 1D9₁₆.
Leading zero digits do not change an integer's magnitude, so 00731₈ and 731₈ produce the same hexadecimal integer. This is numeric conversion, not fixed-width byte formatting.
Only 0 through 7. Digits 8 and 9 are not part of base-8 notation and are rejected rather than removed.
Each octal digit expands to three binary bits. After joining the bits, regroup from the right in sets of four; each four-bit group maps to one hexadecimal digit.
377₈ is binary 011 111 111. Regrouped into four-bit units, that is 1111 1111, which maps to F F in hexadecimal.
Not for an integer conversion. Leading zero digits do not change the magnitude, so 0377₈ and 377₈ both convert to FF₁₆.
Yes. A leading minus sign is treated as the mathematical sign, so -377₈ converts to -FF₁₆. The tool does not infer a two’s-complement width.
Permission bits are naturally grouped in threes, and each three-bit group maps to one octal digit. This converter treats an entry such as 755 as the numeric octal value; it does not interpret permission semantics.
No. It preserves numeric value, not display width. If fixed-width formatting matters, add the required leading zeros after conversion.
Yes, within practical browser limits. The validated integer is converted with BigInt instead of floating-point Number arithmetic.
Related Tools
Convert HEX color codes into RGB color values.
Convert number base values.
Convert Base64 encoded data into hexadecimal values.
Convert hexadecimal values into Base64 encoded data.
Convert binary values into hexadecimal numbers.
Convert hexadecimal values into binary numbers.