Octal to Binary Converter
Convert octal (base 8) numbers to binary by expanding each digit to 3 bits. Used for chmod Linux permission analysis. Free and instant.
Pro Tip: Need to convert between Decimal, Binary, Hex & Octal all at once?
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Octal Digit to Binary (3-bit) Mapping
0 → 000
1 → 001
2 → 010
3 → 011
4 → 100
5 → 101
6 → 110
7 → 111
Chmod 755 in Binary
Linux permission chmod 755: 7=111 (rwx), 5=101 (r-x), 5=101 (r-x) = binary 111 101 101. Each bit = read(4), write(2), execute(1) permission.
Frequently Asked Questions
How do I convert octal to binary?
Replace each octal digit with its 3-bit binary: 0=000, 1=001, 2=010, 3=011, 4=100, 5=101, 6=110, 7=111. Example: 37 = 011 111.
What is 755 in binary?
755₈ = 7→111, 5→101, 5→101 = 111101101. This represents rwxr-xr-x Linux permissions.
Why are octal and binary related?
Because 2³=8. Three binary bits represent exactly 8 values (0-7), matching exactly the 8 octal digits. This makes conversion a simple 1-digit-to-3-bits substitution.