How does Google Ads decide who is a new customer?

By the HonestTag team · Published October 26, 2026

You told Google Ads to find new customers. Now it has to work out who is new.

The settings

Google's table lists New Customer Value and New Customer Only for Search, Performance Max, Shopping and Demand Gen (Google Ads Help):

• New Customer Value: "Bid higher for new customers than existing ones," with value-based bidding. The table says "At least one Purchase conversion goal is required," and Google writes: "We recommend New Customer Value for all advertisers with purchase conversion goals."
• New Customer Only: "Only bid for new customers," with value-based or cost-based bidding. Google recommends it "only if you have strict budgets for customer acquisition, or have non-purchase conversion goals like lead generation," and says "You should set up a separate campaign to reach existing customers when using this mode."

The problem: Google decides who is new on its own data

• Auto-detection has gaps. If your Google Ads conversion tracking is set to track purchases, Google says it "can automatically create an audience list based on up to the last 540 days of campaign activity and tracked purchases." Google calls this method "less comprehensive because users can remove cookies and opt out" (Google Ads Help).
• No purchase in 540 days. Under auto-detection, Google's reporting counts someone as new when "They haven't made a purchase within the last 540 days" (Google Ads Help).
• New-only is not strict. Google says "In some instances, your 'New customers only' ads might be shown to returning customers as well due to privacy and technical reasons" (Google Ads Help).

What changed in October 2025

Google's reports have an Unknown segment: conversions "from customers we can't report about due to policies around legally or culturally sensitive categories or conversions we cannot identify as new or existing due to measurement limitations on iOS and/or user-level personalization settings." Google says that "As of October 2025," it has "improved our ability to estimate if an 'Unknown' customer is a new or existing customer," and that this "Is based on your past campaign performance" (Google Ads Help). So whether some of those customers show up as new rests on Google's estimate.

Three ways to tell Google who is new

• Auto-detection, the default above.
• Audience lists. Google says you can "designate audience lists via Customer Match (CRM and CDP connectors through Google Ads Data Manager, Conversion Based Customer Lists, GA4 Audiences and/or Direct Upload) or by using tag-based remarketing lists, if applicable." If a customer list has "less than 1,000 members," Google says "the campaign's ability to enable new customer acquisition successfully may be impacted" (Google Ads Help).
• A parameter on the conversion. Google says that if you send "the new vs. existing customer parameter in your conversion tracking tag, that parameter is used instead of Google auto-detection" (Google Ads Help).

Google also says "Customer acquisition reporting only works with 'Purchase' conversions in Google Ads," and that a purchase conversion "can be tracked with Google tag, Google Tag Manager, Shopify, Firebase, Google Analytics, and offline conversion imports" (Google Ads Help).

For Shopify, Google recommends its Google & YouTube app and says: "On an upgraded thank you page, it also automatically identifies new customers based on whether it is their first order in the Shopify store" (Google Ads Help).

What a merchant can do

1. Check which source sends your Purchase conversions and whether it sends a new or returning value.
2. If you rely on auto-detection, designate an audience list of existing customers as well.
3. Look at how many conversions Google could not identify as new or existing before you trust the new customer count.
4. Count new customers from your own orders for the same days, and compare that with what Google reports.

What HonestTag does

• HonestTag shows what Google Ads reports beside the new customers whose first recorded ad click or ad-tagged link was Google's.
• Your store decides who is new. HonestTag marks each order new or returning from Shopify's own customer order count at the time of the order, not from a cookie. A guest checkout counts as new.
• On a paid plan, new and returning orders get their own actions: HonestTag_Purchase_NC, HonestTag_Purchase_RC, and HonestTag_Purchase_FCNC for new customers whose first recorded ad click or ad-tagged link was Google's. They are created as secondary actions, so they do not change your bidding unless you promote one or add it to a custom goal. A new customer order lands in HonestTag_Purchase_NC, and in HonestTag_Purchase_FCNC as well when that first click was Google's, so bid on one action per campaign.
• Google's own field, if you turn it on. A switch on the Google Ads card adds Google's new or returning customer field to each purchase HonestTag sends to Google Ads, and to the purchase it sends to Google Analytics if that is set up. Guest checkouts and orders whose customer history could not be read leave the field out.
• The limit. HonestTag counts a first order with your store as new; Google's auto-detection looks back 540 days, so the two counts can differ. How Google uses the field in bidding is Google's call.

Details are in the HonestTag conversion actions and new vs repeat signals.

Frequently asked questions