Octal to hex converter
Enter a octal number and get its hex value instantly, plus the other bases and the step-by-step working. Handles huge numbers, negatives and fractions.
Working for 7558
Multiply each digit by its place value
- 7 × 8^27 × 64= 448
- 5 × 8^15 × 8= 40
- 5 × 8^05 × 1= 5
Add them up: 493 in decimal.
Divide by 16, keep the remainders
- DivisionQuotientRemainder
- 493 ÷ 1630D (13)
- 30 ÷ 161E (14)
- 1 ÷ 1601
Read the remainders from the bottom up: 1ED.
How to convert octal to hex
- Octal and hex don’t line up digit-for-digit (3 bits vs 4), so go through binary.
- Expand each octal digit to 3 bits, then regroup the bits in fours from the right.
- 17 = 001 111 → 0000 1111 = F.
Octal survives mainly in Unix file permissions (chmod 755), in some older systems, and in C/Python literals such as 0o755. Hex is the shorthand for bytes: colour codes (#FF8800), memory addresses, MAC addresses, Unicode code points and hash digests are all written in it.
Related conversions
Binary to hex · Octal to binary · Octal to decimal · Decimal to hex · Hex to octal · any base 2–36 · signed (two's complement)
Questions people ask
How do you convert octal to hex?
Octal and hex don’t line up digit-for-digit (3 bits vs 4), so go through binary. Expand each octal digit to 3 bits, then regroup the bits in fours from the right. 17 = 001 111 → 0000 1111 = F.
What is 755 in hex?
755 in octal (base 8) is 1ED in hex (base 16).
Does it handle negative numbers and fractions?
Yes. A leading minus sign is kept, and digits after a point are converted too. Some fractions that end in one base repeat forever in another (0.1 in decimal is 0.000110011… in binary), so the result is cut at 24 digits and marked as repeating.
Is there a size limit?
No practical one. The converter uses arbitrary-precision integers (JavaScript BigInt), so 64-bit, 128-bit and longer values convert exactly, without rounding.
Why is there no arithmetic in the working?
Every octal digit maps to a fixed group of bits, so conversion is a lookup rather than a calculation.