Set up a campaign experiment

After you’ve finished making edits to your draft, you can create an experiment from your draft and compare how your experiment performs against your original campaign over time. The experiment shares your original campaign’s traffic (and budget) and lets you test changes to your campaign so you can make more informed decisions on which tactics give you a better return on investment.

This article explains how to set up an experiment.  For more background about experiments, read About campaign drafts and experiments. 

Things to note about experiments

  • Experiments are only available for Search and Display Network campaigns. You won’t be able to create an experiment for Video, App, or Shopping campaigns.
  • You can schedule up to 5 experiments for a campaign, but you can only run one experiment at a time.
  • It may take some time for your experiment’s ads to complete the review process and to start running, depending on the size of your original campaign. You may want to schedule your experiment to begin in the future to prevent your experiment from beginning before your ads have been reviewed.
  • You can decide what percentage of your original campaign’s budget that you want to allocate to your experiment. For Search campaigns in the new AdWords experience, you can also split your experiment by a cookie-based split or a search-based split. These experiments can help you see which campaign version performs better. You can then decide if you want people to see only your experiment or your original campaign, or show people both randomly.
  • In Display campaigns, we always use cookie splits to ensure that users only ever see the experiment or your original campaign.
  • As your experiment runs, you can monitor its performance

If you make changes to your original campaign, those changes won’t be reflected on your experiment. Making changes to either your original campaign or experiment while your experiment is running may make it harder to interpret your results.

Keep in mind

If you select the cookie-based split option, and you use audience lists, you should have at least 10,000 users in the list to run an experiment. If you have less users than that, your results may be less accurate. 

Before you begin

You need to create a draft before you set up a campaign experiment. If you haven’t yet created a draft, read Set up a campaign draft.


The new Google Ads experience is now the exclusive way for most users to manage their accounts. Note, automatic targeting is only available in the new Google Ads experience.

Set up an experiment

  1. Sign in to your AdWords account.
  2. Click All drafts from the menu on the left, then click the name of the draft you’d like to edit.
  3. Click the Apply… button on the top right corner.
  4. Select Run an experiment.
  5. Enter a name for your experiment. Your experiment shouldn’t share the same name as your campaigns and other experiments.
  6. Choose a start date for your experiment.
  7. If you’d like to manually end your experiment, select “No end date.” Otherwise, choose an end date for your experiment.
  8. Enter a percentage of the original campaign’s traffic you’d like to allocate to your experiment. This is also the percentage of the original campaign’s budget you’ll be allocating to your experiment.
  9. Click Create to finish creating your experiment.

Fix issues creating an experiment

In some instances, you may encounter an error when trying to create an experiment. Here are a few reasons why this could happen, along with steps you can take to fix these errors.

  • Your original campaign has been removed: Try creating a draft from a different campaign.
  • Your original campaign already has a shared budget: Remove your campaign’s shared budget. Learn how.
  • Your original campaign already has an experiment running or scheduled during your selected dates: Try selecting dates that don’t coincide with another experiment.
  • Your campaign has features that aren’t supported by experiments: Try selecting a different campaign to convert into an experiment. Learn which features aren’t supported by experiments.

What you can do when you're ready to end your experiment

If you’re happy with your experiment’s results, you can apply your experiment to the original campaign or convert your experiment into a new campaign.

  • If you apply your experiment to your original campaign, the changes you were testing in your experiment will be applied to your original campaign.
  • If you convert your experiment into a new campaign, your original campaign will be paused and your experiment will show up in “All Campaigns” with the same budget and dates as your original campaign.

In both instances, your experiment’s performance data will be preserved. Learn more about how to apply your experiment.

If you prefer to simply end your experiment, you can do that by changing the end date of your experiment so it stops running at the close of the day. Learn more about making changes to your experiment.

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