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, you're charged for clicking 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 are 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, ads with extensions also often have a higher actual CPC due to competition for prominence on the search results page. However, you can often get more clicks for less money by using ad extensions, as opposed to increasing your position.
Your actual CPC for ads with extensions is calculated the same way as for ads without extensions — you pay just enough to beat the Ad Rank of the advertiser with the next highest Ad Rank or the minimum Ad Rank necessary to appear in that position. The Ad Rank for your ads with extensions is adjusted for the expected impact of ad extensions and other ad formats by taking into account the relevance, clickthrough rates, and the prominence of your extensions. The more prominence your ad receives, the more impact ad extensions will have on your Ad Rank. This means that a moderate amount of prominence may have little or no impact on your actual CPC, but a large amount of prominence may have a larger impact on your CPC. Learn more about actual cost-per-click (CPC).