crypt() generates MD5 hashes such as:

$1$bp2kK.9.$P1X0o32vzF1C/KPxY22AJc

in the following format:

$1$        # this indicates that it is MD5
bp2kK.9.   # these eight characters are the significant portion of the salt
$          # this character is technically part of the salt, but it is ignored
P1X0o32v   # the last 22 characters are the actual hash
zF1C/KPx   # they are base64 encoded (to be printable) using crypt's alphabet
Y22AJc     # floor(22 * 6 / 8) = 16 (the length in bytes of a raw MD5 hash)