There’re a number of factors to how many keywords you should have in each ad group. That will differ for every advertiser and it’s important to have an idea of what you’d like to achieve before deciding how many keywords you should have.
The number of keywords you have in each ad group affects Click Through Rates (CTR), Quality Scores and Conversions. Getting this wrong can lead to campaign failure. These metrics should help you decide how many to include in each ad group.
First you’ll start with keyword research. That will inform you how many keywords to include in each group and how you will manage and optimise them.
Here are some tips to help you decide this:
Minimum 5 keywords
The Google system recommends that you have at least 5 keywords in each ad group. If you check the Opportunities tab, you’ll see suggestions to include more keywords in any ad groups that have fewer than 5.
And adding more will push your Search Health Score higher, and closer to 100%. Of course these suggestions are based on Google’s knowledge of your campaigns and it will try to pick closely related keywords.
However, adding keywords just for the sake of it could harm your campaigns. Some keyword suggestions may not be relevant to the ad groups and that could affect conversions, Click Through Rates (CTR) and Quality Scores.
Maximum 20 Keywords
Don’t add more than 20 keywords per ad group. You want to keep your ad groups tightly themed and the fewer keywords you have the better.
Too many keywords leads to low click through rates and poor quality scores. And that’s because it’s difficult to have every keyword included in the Ads.
Keywords should always be included in the Ads. When people see their keyword in the Ad they’re more likely to click and this boosts overall performance.
Follow the rule of two
The rule of two states that every keyword in the Ad group should have at least two primary words. It ensures that you don’t add too many keywords and that they’re all related to each other.
So, the keyword “Hire Google AdWords Expert” has at least two primary words ‘AdWords’ and ‘Expert’. So these two should be part of every keyword that’s included in the ad group.
And the following would be closely related to it because they follow the ‘rule of two’:
⁃ AdWords Expert Help
⁃ AdWords Expert
⁃ AdWords Expert Support
⁃ Find AdWords Expert
However, some of these would be fine in their own ad groups. The point is that ad groups should be tightly themed and all keywords should be related.
So, first start with keyword research and then group them according to themes. Remember to follow the ‘rule of two’ and you’re sure to have targeted ad groups and successful campaigns.