down vote acceptedClustered IndexOnly one per tableFaster to read than non clustered as data is physically stored in index orderNon Clustered IndexCan be used many times per tableQuicker for insert and update operations than a clustered index

The difference is that, Clustered index is unique for any given table and we can have only one clustered index on a table. The leaf level of a clustered index is the actual data and the data is resorted in case of clustered index. Whereas in case of non-clustered index the leaf level is actually a pointer to the data in rows so we can have as many non-clustered indexes as we can on the db.