General Terms in Adsense Report

There are quite a lot of people who do not know what eCPM is. Below is the Adsense Report for illustration purpose:

Page impressions Clicks Page CTR Page eCPM Earnings

50 2 4.00% $6.60 $0.33

These numbers are calculated as follows:

Page Impressions (50)

This is simply a count of the number of times adverts have been displayed on your page. It includes occasions when your page has been displayed in search engine caches, so the count may not match your log files exactly. It counts pages not ads - if you had more ad units, link units or referral units on the page, then the page impressions would still be 50.

Clicks (2)

This is simply a count of the number of times that any advert has been clicked on the page - ie: 2 clicks.

Page CTR (4.00%)

This is a derived number: "Click Through Rate". There are often many different ways of calculating derived numbers, but in this example it is most easily and accurately produced using the calculation:
CTR = 100 x Clicks / Page ImpressionsIn this case the calculation is:
CTR = 100 x 2 / 50 = 4.00%This the rate of clicks per hundred, a figure often used for comparing performance of different ad placements on a page.

eCPM ($6.60)

This is another derived number: "effective Cost Per Thousand" (M is the latin symbol for a thousand). It is often used for comparing ad placements and overall performance of ads or pages. It is calculated using the formula:
eCPM = 1000 x Earnings / ImpressionsIn this case, the calculation is:
eCPM = 1000 x $0.33 / 50 = $6.60

Earnings ($0.33)

This is the amount of money that you will be paid by Google, at some point in the future, for the clicks. The calculation is:
(The sum of all the click values) x (Your percentage rate)Your percentage rate is only known to Google, but as we have assumed a 70% payment to you, the calculation is:
Earnings = ($0.34 + $0.13) x ( 70 / 100 ) = $0.329 ($0.329 is rounded to two decimal places in the report, to $0.33)

Source: http://lekieuanhblogfree.blogspot.com/2010/02/general-terms-in-adsense-report.html