Your revenue can be roughly calculated using the following formula from your report data:

Revenue = (CPM x Impressions)/1000

CPM = Cost Per Mille

This will apply for the time period of the report you are using the data from. 

It must be noted that there are several factors that can affect this metric and this formula is only intended to provide an estimate of revenue for a selected period. For more details on the factors that affect monthly revenue, see our help guide here: Why is my revenue so different from last month?