About extensions and your actual cost-per-click
When extensions show, an ad is more prominent and, typically, performs better—more people click on it. This article explains how extensions might impact your actual cost per click (CPC). For a general introduction to extensions, start with About extensions. For more on reporting data, head to See extension performance.
There's no cost to add extensions to your campaign, but you're charged as usual for clicks on your ad, as well as for certain interactions that extensions provide. For example, when a person clicks on a download button (app extensions), on a call button (call extensions), on a directions icon (location extensions), and so on. Clicks on review extensions and seller ratings are an exception: we don’t charge you for these. AdWords charges no more than two clicks (per impression) on each ad and its extensions.
The cost of clicks on extensions is set in the same way as headline clicks: the most you'll pay is what's minimally required to keep your extensions and ad position. Learn more about actual cost-per-click (CPC).
Just as ads in higher positions usually have a higher actual CPC (due to competition and, in part, to higher Ad Rank thresholds), ads with extensions also often have a higher actual CPC due to increased prominence. However, note that the incremental cost of adding more extensions to your ads is often lower than the incremental cost of moving up a position on the search results page. That means you can often get more clicks for less money by using ad extensions than by increasing your position.
Your actual CPC for ads with extensions is calculated the same way as for ads without extensions — you pay the minimum amount necessary to hold your ad position and to keep the ad extensions you have in that position. For example, if your Ad Rank places you immediately above search results (Ex: in the fourth position) with location extensions and sitelinks, you’ll pay the minimum amount necessary to keep that position -- and meet the relevant thresholds tied to that position -- with those extensions. Learn more about actual cost-per-click (CPC).