What is the difference between CPC, CTR, CPM, CPT?

CPM – Cost Per Mille – cost per 1,000 impressions.

CPC – Cost Per Click.

CTR – Click-through rate, the ratio of clicks to impressions. For example, if the number of impressions is 15,000 and the number of clicks is 30, then CTR=30/15,000=0.2%.

CPT – Cost Per Thousand – cost per 1,000 unique impressions.