really depends on what was used to create the hash
md5() and sha1() are rather weak PHP 5.5 is often used now.
A cryptographic salt is data which is applied during the hashing process in order to eliminate the possibility of the output being looked up in a pre calculated list often called a rainbow table, a salt is a bit of additional data which makes your hashes significantly more difficult to crack.
for example your hash may comprise of:
bd95 - Algorithm
amfisb - Algorithm option
3i1padirh7jgq74eaurmndh21g8 - Salt
decvbmfrmv8kfknloso04jiknb6orfp17cmvgujeuq9jhorjadr02t7henbnh000k0 - hashed data (password)
try goggling for md5() sha1() and PHP 5.5