CPM means cost per mille here mille is the french word its meaning is thousand so CPM can also be pronounced as cost per thousand.
CPM is the cost structure which refers the amount that needs to be paid by the advertiser based on the impression.
Here total ad spend is total money spend for ads.
Total Measured ad impression means total number of times ads were delivered on the site.
The total price paid in a CPM deal is calculated by multiplying the CPM rate(its nothing but cost for thousand impression) with the total number of impressions served (total measured ads impression).
For example, If a publisher is getting ₹ 500,000 from a campaign for delivering 5M impression. Then What will be the CPM rate?
Writing above details in simple equation form:
5,000,000 IMPs= ₹500,000
(also called CPM) 1000 IMPs= ?
Next, just cross multiply it, CPM = (500,000 x 1000)÷5,000,000
So now, CPM = ₹ 100