Octal Converter
Convert text to octal (base 8) and back. Also convert between decimal and octal numbers.
Enter octal values separated by spaces (e.g., 110 145 154 154 157)
Common Octal Values
A = 101
B = 102
Z = 132
a = 141
z = 172
0 = 060
9 = 071
SP = 040
Octal Digits
Octal uses digits 0-7 only. Each octal digit represents 3 binary bits.
0 = 000
1 = 001
2 = 010
3 = 011
4 = 100
5 = 101
6 = 110
7 = 111
What is Octal?
Octal is a base-8 numeral system that uses digits 0-7. It was commonly used in early computing because it provides a convenient way to represent binary data (each octal digit represents exactly 3 binary bits).
Octal in Computing
Octal notation is still used in various computing contexts:
- Unix permissions: File permissions like 755 or 644
- C/C++ literals: Numbers prefixed with 0 (e.g., 0755)
- Escape sequences: \nnn format in strings
- ASCII encoding: Characters can be represented in octal
Converting Octal
Octal to Decimal
Multiply each digit by its positional power of 8:
145₈ = 1×64 + 4×8 + 5×1 = 64 + 32 + 5 = 101₁₀
Decimal to Octal
Repeatedly divide by 8 and collect remainders:
101 ÷ 8 = 12 r5, 12 ÷ 8 = 1 r4, 1 ÷ 8 = 0 r1 → 145₈
Octal in Geocaching
Octal appears in geocaching puzzles because:
- Computing theme: Perfect for tech-themed caches
- Distinct format: Only uses digits 0-7
- Unix references: Permission puzzles are common
- Historical: Early computing nostalgia
Recognizing Octal
Look for these signs:
- No 8s or 9s: Octal only uses 0-7
- Leading zeros: Programming notation like 0755
- Three-digit groups: Often padded to 3 digits for ASCII
- Unix hints: References to permissions or chmod
Octal ASCII Table (Common Characters)
| Char | Octal | Decimal |
|---|---|---|
| A-Z | 101-132 | 65-90 |
| a-z | 141-172 | 97-122 |
| 0-9 | 060-071 | 48-57 |
| Space | 040 | 32 |