The two main modes
New Customer Value bids higher for new customers while still reaching returning ones, and needs a purchase conversion goal with Target ROAS or Maximize conversion value. New Customer Only bids exclusively for new customers. Google recommends it for strict acquisition budgets or non-purchase goals like lead generation, and it also works with Maximize conversions or Target CPA. It's available on Search, Performance Max, Shopping and Demand Gen.
How Google identifies existing customers
Google uses Customer Match lists, website or app remarketing lists, a new customer parameter in your conversion tag, and auto-detection, which builds a list from up to 540 days of campaign activity and tracked purchases. Customer lists need at least 100 active members, and Google says lists under 1,000 may weaken results.
The lead gen catch
Auto-detection only activates if you already track Google Ads purchase conversions, and the conversion tag parameter only works with Purchase conversions. A lead gen campaign usually doesn't track purchases, so its definition of an existing customer is whatever lists you provide. With none, 'only bid for new customers' has little to apply. We cover this in 'bid for new customers' is guessing until you upload your customers.
Common questions
Does the new customer acquisition goal need a customer list?
Not strictly, but it works far better with one. Auto-detection and the conversion tag parameter only work when you track Google Ads purchase conversions, and Google recommends supplementing it with Customer Match lists for more accurate detection.
Which campaign types support it?
Search, Performance Max, Shopping and Demand Gen.
Can I use it for lead generation?
Yes. Google recommends New Customer Only mode for non-purchase goals like lead generation, and it supports Maximize conversions and Target CPA as well as value-based bidding.
How large must a customer list be?
At least 100 active members in at least one network for the list to be used. Google says lists with fewer than 1,000 members may weaken new customer acquisition results.
What counts as a new customer?
Anyone Google can't match to an existing-customer source: your Customer Match lists, remarketing lists, conversion tag data, or its auto-detected list of past purchasers.