The price an advertiser is charged for each click the ad receives. CPC = total cost of campaign ÷ number of clicks.
CPC rates minimize the risk for advertisers since they only pay when someone actually clicks on their ad – but rates can go quite high, up to as much as $20 per click or more, especially when targeting high-demand audiences or popular phrases on Google.
eCPC means effective cost per click and is used to show what the CPC would have been if the advertiser purchased clicks instead of impressions or conversions.