--- title: "How to blend Facebook Ads and Google Ads custom conversions" slug: "how-to-blend-facebook-ads-and-google-ads-custom-conversions" description: "Learn to blend Facebook Ads and Google Ads custom conversions effectively, ensuring compatibility for accurate reporting and insights." updated: 2026-05-04T06:40:20Z published: 2026-05-04T06:40:20Z --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.supermetrics.com/llms.txt > Use this file to discover all available pages before exploring further. # How to blend Facebook Ads and Google Ads custom conversions This article guides you on how to build a [Supermetrics data blend](/v1/docs/data-blending) that includes custom conversions from multiple ad platforms, Facebook Ads and Google Ads specifically, when these platforms surface conversions differently. Facebook Ads exposes each custom conversion as its own metric, while Google Ads provides a single Conversions metric that must be split by the Conversion type dimension. To align these fields, use a [Custom field](/v1/docs/custom-fields) to extract a single Google Ads conversion metric per conversion type, and when needed, add multiple instances of Google Ads in the same blend to avoid field incompatibility. To use custom conversions across both Facebook Ads and Google Ads in your blend, you’ll need to complete the following steps: 1. Create a Supermetrics Custom field in Google Ads to isolate a specific conversion type as a standalone metric. 2. Blend Facebook Ads and Google Ads, ensuring the fields are compatible across the data sources. 3. Optionally add multiple Google Ads instances to support Google Ads non-conversion metrics alongside conversion metrics in the same blend. ## Prerequisites - Access to the [Facebook Ads](https://docs.supermetrics.com/docs/facebook-ads-connection-guide) and [Google Ads](https://docs.supermetrics.com/docs/google-ads-connection-guide) connectors with access to the required data source accounts. - Knowledge of your Facebook custom conversions (names & IDs) and the matching Google Ads conversion names you want to compare. - A subscription that includes Supermetrics Data blending and Custom fields for the data destination you are using. ## Instructions ### Step 1: Identify target conversions You’ll need to decide which conversions you need to report side-by-side. For example: - Facebook Ads: “Webinar signups” custom conversion metric - Google Ads: “Webinar signup” Conversion type within the overall Conversions metric > [!NOTE] > Note > > Take note of the exact conversion names you want to match across platforms to avoid a mismatch later. ### Step 2: Create a Supermetrics custom field for Google Ads 1. On the [Supermetrics Hub](https://hub.supermetrics.com/), go to **Custom fields** under **Manage**. 2. Click **New custom field**. 3. Select **Metric** as the field type. 4. Select **Google Ads** as your data source and click **Next**. 5. Select **Condition** as the transformation. 6. In the **IF** section, choose **Conversion type**EQUALS “Webinar signups”. 7. In the **THEN** section, select **Data source field** and choose **Conversions** from the drop-down menu. 8. In the **ELSE** section, select **Static value** and enter “**0**” in the text field. 9. Give the field a descriptive name, for example, “Webinar signups (GAds)”, and click **Create custom field**. > [!NOTE] > Note > > You can repeat this step to create multiple per-type metrics if you plan to compare several custom conversions from Facebook Ads. For example, Google Ads Conversions - Purchase, Google Ads Conversions - signups. ### Step 3: Build your blend 1. On the [Supermetrics Hub](https://hub.supermetrics.com), go to **Data blending** under **Manage**. 2. Click **Create new blend**. 3. Select **Union** and select **Next step**. 4. Select **Facebook Ads** as your first data source and the accounts to use. 5. Click **Add Fields**, and add Date, your Facebook Ads custom conversion metric(s) and any descriptive dimensions you need for your reporting. 6. Select **Google Ads** as your second data source and the accounts. 7. Click **Add Fields** in the Google Ads column, and add Date, and the custom field you created, “Webinar signups (GAds)” in this example. Include the base Conversions metric only if needed for quality assurance, not for the blend metric. 8. Map the custom conversions and the dimensions to both data sources. In this example, map the Facebook Ads custom conversion metric with the custom field you created for Google Ads, the date with the date. 9. Click **Next Step** and add a name for your blend. 10. Click **Create blend** to save your blend. ![](https://cdn.document360.io/a13cead5-eaae-456f-9bd1-0941d590c0e3/Images/Documentation/data-blending-blend-FA-and-AW-custom-conversions-1.png) After completing these steps, you get a unified table where both Facebook and Google provide a comparable conversion metric per day (or your chosen frequency), ready for side-by-side charts or aggregated KPIs. ### Step 4 (optional): Adding multiple Google Ads instances to your blend The Google Ads API doesn't allow combining standard delivery metrics, such as cost or impressions, with the Conversion type dimension in the same request. Because the custom field you created relies on Conversion type, you can't include it in the same Google Ads instance as delivery metrics. To use conversion metrics together with standard delivery metrics, include two separate Google Ads instances in your blend — one that pulls conversion metrics and one that pulls delivery metrics. 1. Add a new **Google Ads** instance to the blend that includes only that custom metric, and map the dimensions to the other data sources in the blend. 2. All metrics and dimensions from the first instance should be automatically mapped to the new instance. **Unmap** the Google Ads conversion metrics and the Google Ads basic metrics. 3. Keep each instance minimal, include only the fields required for the blend to reduce conflicts. ## ![](https://cdn.document360.io/a13cead5-eaae-456f-9bd1-0941d590c0e3/Images/Documentation/data-blending-blend-FA-and-AW-custom-conversions-2.png) ## Best practices - Create one custom field per Google Ads conversion type you want to compare. - Limit the dimensions in the blend to what is strictly necessary and expand later if needed. - Use consistent naming conventions for custom fields to keep dashboards easy to maintain. - Document the exact logic and target conversion names in your notes. ## More resources - [How to create and manage data blends](/v1/docs/how-to-create-and-manage-data-blends) - [About Supermetrics custom fields](/v1/docs/about-supermetrics-custom-fields)