I don't think there's any simple metric. Like, no one can say you should have twenty-seven commas per page or anything like that.
The first question would be, Do you have commas in inappropriate places? If you have sentences like, "Bob walked, to, the store, slowly" then yes, there are too many commas. But a sentence that contains a list could legitimately have many commas. Like, "He found a bottle, three coins, two keys, a small metal box, a pack of matches, some scraps of paper, and a patridge in a pear tree."
The real problem is not the number of commas per se, but whether they are being used properly. If they are, then I wouldn't even think about it.
If you think you have too many commas, and they are all used appropriately, it may be that your problem is that your sentences are too complex. If you have too many clauses in each sentence that can indirectly result in too many commas.
As Tylerhams said in a comment, perhaps if you gave a couple of sample sentences folks here could give a more specific reply.