Most Google Ads campaigns optimize for conversions without distinguishing whether those conversions come from new customers or existing ones. If someone who bought from you last month buys again, that counts as a conversion. It is good for your business, but it is not customer acquisition — and a campaign optimizing for total conversions will happily re-convert existing buyers instead of finding new ones, because existing buyers are easier and cheaper to convert.
The New Customer Acquisition (NCA) goal was added to Performance Max and Shopping campaigns to solve this. It tells Google’s algorithm to weight new customer conversions more heavily, actively prioritizing audience expansion over re-engagement.
The Two NCA Modes
New Customer Value Mode: Google still optimizes for all conversions, but new customer conversions are assigned a higher value than repeat customer conversions. The extra value you assign signals to Smart Bidding that acquiring a new customer is worth more than a repeat purchase of the same order size. The campaign bids more aggressively in auctions that are more likely to result in a new customer conversion.
Use this mode when: you want a balance between new customer acquisition and re-converting existing customers, but you want to skew the bidding toward new customers.
New Customer Only Mode: Google is instructed to optimize only for new customer conversions. It will not avoid showing ads to existing customers entirely, but it assigns zero value to repeat purchases from existing customers in its optimization model. The campaign effectively ignores repeat purchase conversions when making bid decisions.
Use this mode when: new customer acquisition is your primary objective and you are comfortable accepting lower overall reported conversion volume in exchange for a higher proportion of new buyers.
New Customer Only Mode typically results in lower total conversion counts and higher CPAs compared to New Customer Value Mode — because Google is deliberately avoiding the “easy” re-conversion wins. This is the correct trade-off if lifetime value of a new customer is significantly higher than a single repeat purchase.
How Google Identifies New Customers
This is the part most guides skip, and it is where implementation accuracy matters most.
Google identifies new customers using two methods:
Customer lists: You provide Google with a Customer Match list of your existing buyers. Google uses this list to identify users who are already your customers. Anyone not on the list who converts is counted as a new customer.
New customer signal from your conversion tag: You add a parameter called new_customer to your purchase conversion tag. When this parameter is set to true, Google counts the conversion as a new customer acquisition. When it is false or absent, the conversion is treated as a repeat purchase.
The most accurate implementation uses both methods together. Customer Match handles users who are known existing customers (even if they have not bought recently enough to be in your DataLayer data). The new_customer parameter handles real-time identification at the point of conversion.
Implementing the new_customer Parameter in GTM
The new_customer parameter needs to be passed to your Google Ads Conversion tag at the time the purchase conversion fires.
Your ecommerce platform or backend needs to determine whether the purchaser is a new customer and make that information available on the order confirmation page. On Shopify, you can check whether the customer’s order count is 1 (their first order) — if it is, they are a new customer.
Step 1: Pass new_customer to the DataLayer on the order confirmation page.
In Shopify, in the Additional Scripts section (or via a custom pixel for Checkout Extensibility), add this alongside your existing purchase DataLayer push:
<script>
window.dataLayer = window.dataLayer || [];
window.dataLayer.push({
'event': 'purchase',
'ecommerce': {
'transaction_id': '{{ order.order_number }}',
'value': {{ checkout.total_price | divided_by: 100.0 }},
'currency': '{{ checkout.currency }}'
},
'new_customer': {% if customer.orders_count == 1 %}true{% else %}false{% endif %}
});
</script>
The Liquid conditional {% if customer.orders_count == 1 %} evaluates whether this is the customer’s first order. If it is, new_customer is set to true.
Note: customer.orders_count counts from the moment the current order completes. So on a first purchase, it equals 1. On a second purchase, it equals 2. This makes it a reliable check for new vs. returning customers at checkout.
Step 2: Create a DataLayer variable in GTM.
In GTM, create a new DataLayer Variable:
- Name:
DL - New Customer - Data Layer Variable Name:
new_customer
Step 3: Add the new_customer parameter to your Google Ads Conversion tag.
Open your Google Ads Purchase Conversion tag in GTM. In the tag configuration, find the Additional Parameters section. Add a new parameter:
- Parameter Name:
new_customer - Parameter Value:
{{DL - New Customer}}
Publish the GTM container.
Verification: Complete a test purchase using a new Google account (an account that has not purchased from your store before). In GTM Preview mode, verify that the Purchase Conversion tag fired with new_customer: true in the parameters. Then complete a second test purchase with the same account. The second conversion should fire with new_customer: false.
Enabling the NCA Goal in Your Campaign
Once your new_customer parameter is implemented and verified, you can enable the NCA goal in Google Ads.
For Performance Max:
In your PMax campaign settings, scroll to the Bidding section. Look for the “New customer acquisition” option. Select either New Customer Value Mode or New Customer Only Mode.
If using New Customer Value Mode, set the “new customer acquisition value” — this is the additional value Google should assign to a new customer conversion on top of the order’s actual conversion value. A common approach is to use your estimated customer lifetime value minus the first order value. If your average LTV is $300 and your average first order is $80, the additional new customer value you set might be $220.
If using New Customer Only Mode, you do not need to set an additional value — the campaign simply de-weights repeat customer conversions.
For Shopping campaigns:
The NCA goal is available in Standard Shopping campaigns under campaign settings, Bidding, Goal. Select “New customer acquisition” and configure the same options as above.
Do You Need a Customer Match List?
A Customer Match list is not technically required to enable NCA — you can run it on the new_customer parameter alone. But combining both gives better accuracy.
The new_customer parameter identifies customers at the moment of conversion based on your backend data. Customer Match identifies existing customers earlier in the auction process — before a click even happens — which helps Google avoid bidding on high-CPC auctions for users it knows are already your customers.
Without Customer Match, Google has no way to avoid bidding on existing customers until after they convert and the new_customer: false signal comes back. With Customer Match, Google can deprioritize existing customers proactively, which improves NCA efficiency.
If you have a Customer Match list of at least a few thousand buyers, add it to your NCA-enabled campaigns. If your list is smaller or not yet set up, run NCA on the new_customer parameter alone and add Customer Match when you have it.
When NCA Is the Right Strategy
Use NCA when: you have a healthy base of repeat buyers and your campaigns are primarily re-converting existing customers. This is a common situation for stores with high retention rates — the campaign looks efficient because existing customers are easy to convert, but it is not growing the customer base.
Use NCA when: you are in a growth phase and new customer acquisition is the explicit priority, even at higher CPA than repeat purchase conversions.
Do not use NCA when: your business is primarily driven by one-time purchases (low repeat rate categories). If customers rarely buy twice, optimizing for new customer acquisition vs. all conversions makes little practical difference.
Do not use NCA in New Customer Only Mode when: your budget is small and your conversion volume is already thin. New Customer Only Mode reduces the pool of conversions the algorithm can learn from, which can destabilize Smart Bidding in small accounts. New Customer Value Mode is the safer starting point.
Measuring NCA Performance
After enabling NCA, Google Ads will start reporting “New customer conversions” as a separate metric in your conversion columns. Enable this column in your campaign view.
Track the ratio of new customer conversions to total conversions over time. If NCA is working as intended, this ratio should increase — you are capturing a higher proportion of new buyers relative to repeat purchases.
Also track new customer CPA (cost per new customer conversion) separately from overall CPA. New customer CPA will be higher than blended CPA, which is expected. The question is whether new customer CPA is acceptable relative to your estimated LTV for a new buyer.
A new customer CPA of $60 might look high compared to a blended CPA of $25 — but if your average customer LTV is $400 and average first order value is $85, a $60 cost to acquire a customer with $400 LTV is an excellent investment.
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