PHP Manual: Octal to decimal

intfloat octdec(string $octal_string)

Returns the decimal equivalent of the octal number represented by the octal_string argument.

octal_string: The octal string to convert. Any invalid characters in octal_string are silently ignored. As of PHP 7.4.0 supplying any invalid characters is deprecated.

The decimal representation of octal_string

Version	Description
7.4.0	Passing invalid characters will now generate a deprecation notice. The result will still be computed as if the invalid characters did not exist.

Example #1 octdec example

<?php
echo octdec('77') . "\n";
echo octdec(decoct(45));
?>

The above example will output:

63
45

Note:
The function can convert numbers that are too large to fit into the platforms int type, larger values are returned as float in that case.

octdec