A call asset is a Google Ads addition that shows your phone number, or a call button on mobile, alongside your ad. Searchers can ring you directly from the results page without visiting your website. It used to be called a call extension, and many people still use that name.
How a call asset works
You add a phone number as an ad asset at account, campaign or ad group level. On a phone, the ad gets a tappable call button; on a desktop, the number may appear as text that people dial themselves. Google decides when to show it, based on the device, the ad’s position and whether it expects the asset to help.
Enter the number in a normal UK format, either with the leading zero, such as 020 7946 0123, or in international form as +44 20 7946 0123. Use a geographic 01 or 02 number, an 03 number or a mobile. Google does not accept premium-rate numbers, and costly 084 or 087 numbers can put callers off even where they are allowed. Google may also ask you to verify the number, and it should appear on your website.
When call reporting is switched on, Google shows a forwarding number in place of yours. The caller dials that number, the call is routed straight to your line, and Google records the call’s length, time and the caller’s area code. At the time of writing (October 2026), Google forwarding numbers are available for UK advertisers, but check the setting in your account, because availability is decided by country and can change. Calls lasting longer than a length you choose, 60 seconds by default, can be counted as call conversions.
You can schedule the asset so the number only appears when someone can answer, using the asset’s own schedule or the campaign’s ad schedule.
Why it matters
For many UK service businesses, a phone call is the most valuable enquiry there is. Someone with a burst pipe, a locked-out car or an urgent legal problem wants to talk to a person, not fill in a form. A call button removes the steps between the search and the conversation.
It also makes the ad bigger and more noticeable, particularly on mobile. And with forwarding numbers, you can finally see which campaigns and keywords lead to calls, rather than counting them as unexplained enquiries.
Common mistakes
- Showing the number outside opening hours, so calls go to voicemail and are lost.
- Switching off call reporting, then wondering why the account shows no phone leads.
- Counting every call as a conversion, including three-second hang-ups and calls from existing customers about invoices.
- Using a number that is not on the website, which can stop the asset being approved.
- Adding the asset to campaigns where calls are unwanted, such as an ecommerce campaign aimed at online orders.
How to act on it
Add a call asset to any campaign where a phone call is a good outcome. Make sure the number is on your site, switch on call reporting, and schedule it to match the hours your phone is staffed. Then set a call length for counting conversions that reflects a real enquiry for your business: 60 seconds suits many trades, while a quick booking line may need less.
Review missed calls weekly. If a campaign drives calls you cannot answer, the problem is staffing or scheduling, not the ads. Where calls are the main goal, a call-only ad may also be worth considering. Setting up call tracking properly is part of how I build accounts in my Google search ads management.