CPI (Cost Per Impression)
Cost Per Impression (CPI) refers to the price or cost per page impression an advertiser will pay to a publisher or advertising network.
If you are a publisher, then CPI is the revenue or money you will earn per page impression generated from a web page.
For example, if an article written by you gets 500 impressions (page views) at a $10 CPM rate, then the CPI from the article will be the following:
Cost Per Impression Rate ($) = CPM rate ($)/1000
If an advertiser offers $10 CPM rate then your earnings from per impression will be = $10
CPM/1000 impressions = $0.01
Now, 500 impressions will earn you 500*0.01 ($) = $5