Octal Converter

Octal Converter reads a base-8 number such as a 755 permission code and returns its decimal, binary and hexadecimal values, with the base you pick as the headline figure.

Only the digits 0 through 7 are accepted: an 8 or a 9 is rejected with a message naming the valid ones, and a leading 0o is stripped before parsing. The binary line is the one worth reading for permissions, because each octal digit is exactly three bits — 755 comes back as 111101101, which is the three rwx triplets as a bit pattern. That is also where the tool stops. It prints numbers in four bases and does not render the letter form, so rwxr-xr-x is still something you read off the triplets yourself. Whole numbers only, and the input has to stay within an exactly representable integer.

Nothing leaves the device: the parse and the reprinting both happen in the browser, with no server call and no record of the codes you looked up.

Decoding a chmod value found in a deploy script, checking what 644 and 600 come to in decimal, converting a legacy octal constant out of old C or Unix source, and getting the bit pattern behind a permission mask.

Also known as: octal to decimal · chmod octal permissions · change octal format