How to Blend Data in Looker Studio

Combining data from different platforms is essential for getting the full picture of your performance, but it's often a manual, time-consuming process. Thankfully, Looker Studio (formerly Google Data Studio) has a built-in feature designed to solve this exact problem. This guide will walk you through exactly how to blend data in Looker Studio, step by step, so you can stop jumping between tabs and start building comprehensive reports.

What Exactly is Data Blending?

Think of data blending as a way to do a VLOOKUP or a SQL join directly inside Looker Studio, but without writing any formulas or code. It allows you to combine up to five different data sources into a single chart or graph. The key to making it work is something called a join key - a common dimension that exists in all the data sources you want to combine.

For example, imagine you want to see your Facebook Ads cost right next to your Google Analytics website sessions in the same time series chart. The one thing both of those datasets have in common is Date. In this scenario, 'Date' is your join key. By blending these two sources using the date, you can visualize how your daily ad spend influences your daily website traffic in a single, unified view.

Common join keys for marketers and business owners include:

• Date
• Campaign Name
• Product ID or SKU
• User ID
• Country

Why You Should Blend Your Data: Common Use Cases

Blending data unlocks a deeper level of analysis that's impossible when your analytics are siloed in different platforms. Here are a few practical scenarios where it comes in handy.

Connecting Ad Spend to Sales Revenue

This is one of the most powerful use cases for data blending. You can combine expense data from advertising platforms with revenue data from your e-commerce or analytics platform to directly measure return on investment (ROI).

• Data Source 1: Google Ads (Metrics: Cost, Clicks)
• Data Source 2: Google Analytics 4 (Metrics: Total Revenue, Conversions)
• Join Key: Date

The result is a single dashboard component that clearly shows how much you spent versus how much you made on any given day, week, or month.

Creating a Unified Multi-Channel Marketing Report

Most marketing strategies don't rely on a single channel. To accurately report on overall performance, you need to pull data from everywhere you advertise. Blending allows you to consolidate this information without manually exporting CSVs.

• Data Source 1: Facebook Ads (Metrics: Amount Spent, Impressions)
• Data Source 2: Google Ads (Metrics: Cost, Clicks)
• Data Source 3: LinkedIn Ads (Metrics: Cost, Leads)
• Join Key: Campaign Name and/or Date

With this blend, you can build a table that compares the performance of campaigns across all your active platforms, helping you see where your budget is working hardest.

Enriching CRM Data with On-Site Behavior

If you connect web behavior to lead quality, you can better understand where your best customers come from. By blending your CRM data with website analytics, you can link specific users to their actions before converting.

• Data Source 1: Salesforce or HubSpot (Dimensions: Lead Source, Status)
• Data Source 2: Google Analytics 4 (Metrics: Sessions, Pages per Session)
• Join Key: User ID (requires proper setup in GA4)

This allows sales and marketing teams to see which landing pages or content pieces are most effective at attracting high-quality leads.

A Step-by-Step Guide to Blending Data in Looker Studio

Now, let's walk through the exact process. For this example, let's assume we want to create a simple chart that shows our Google Ads Cost alongside our GA4 Sessions.

Step 1: Get Your Data Sources Set Up

Before you can blend, you need to have the data sources added to your report. In your Looker Studio report, go to Resource > Manage added data sources and verify that your Google Ads and Google Analytics accounts are present. If not, click "Add A Data Source" to connect them.

Pro Tip: It helps to have consistent field names for your join key. Both GA4 and Google Ads have a Date dimension by default, so we're good to go. If you were using a different source that named it Day, you might want to rename the field for clarity before blending.

Step 2: Start the Blend

You have two primary ways to create a blend:

1. Blend data from a chart: This is the most common and intuitive method. Add a chart (like a basic table) to your report canvas and select it. In the Setup panel on the right, under your chosen data source, click the "BLEND DATA" button.
2. Manage blends from the menu: You can also create a blend from the top menu by navigating to Resource > Manage blends and clicking "Add a blend."

We’ll use the first method for this walkthrough.

Step 3: Configure the Blend Data Panel

After clicking "BLEND DATA," a new configuration window will pop up. This is where the magic happens. On the left, you'll see your first table (the data source associated with the chart you selected). Let’s say this is our Google Analytics 4 data.

• Select the Dimensions and Metrics you want from this source. We’ll add Date as the dimension and Sessions as the metric.

Next, click "Join another table" to add your second data source. A panel will appear asking you to choose your next data source. Pick Google Ads. Now add the fields you need from it: Date as the dimension and Cost as the metric.

Step 4: Configure the Join Conditions

This is the most crucial part. The "Join conditions" column tells Looker Studio how to connect your tables. Click "Configure join" to open the settings.

Here you'll see a few options:

• Left Outer (Default): This includes all the rows from the first (left) table and any matching rows from the second (right) table. This is the one you’ll use most often, as it ensures you don’t lose any data from your primary source.
• Inner Join: This only includes rows where the join key exists in both data sources. This can unintentionally filter out data. For example, if you had sessions on a day with zero ad spend, an inner join would remove that day from your report entirely.
• Right Outer: The inverse of a left join. It keeps all rows from the right table.
• Full Outer: Includes all rows from both tables, regardless of whether they match.
• Cross Join: This combines every row from the left table with every row of the right table. Avoid this unless you have a very specific advanced use case, as it can create massive, unwieldy data sets.

For our example, we want to specify that the Date field in GA4 should connect to the Date field in Google Ads. Looker Studio is smart and will often suggest this automatically. If it looks correct, leave the join operator as "Left Outer" and click save.

Step 5: Save your Blended Data Source

Before you save, give your blended data source a descriptive name at the top of the window, such as "GA4 + Ads - Daily Performance." This will help you identify it later if you need to make changes. When you're ready, click "Save" in the bottom right corner.

Step 6: Visualize Your Blended Data

You will be taken back to your report's canvas. The chart you selected is now powered by your new blended data source. In the Data panel on the right, you’ll see fields from both Google Ads and Google Analytics are now available.

You can drag Date into the Dimension field, and then drag both Sessions and Cost into the Metric fields. Your chart now successfully displays data from two different sources in one place!

Tips & Common Pitfalls to Avoid

Data blending is extremely powerful, but it can be tricky. Here are a few things to watch out for.

• Mismatched Date Formats: A common reason a blend fails or produces inaccurate results is inconsistent date formats between sources. One source might use YYYY-MM-DD while another uses MM/DD/YYYY. Ensure your date fields are standardized to the same data type.
• Choosing the Wrong Join Type: As mentioned, using "Inner Join" can cause you to lose valuable data. For most marketing reports, stick with "Left Outer Join" to ensure your primary data source is fully represented.
• Filtering Issues: Looker Studio filters apply after the blend. This means if you have date-range filters on your page, they will filter the final blended data. However, be aware of filters applied at the data source level, as this can affect the data before it even gets to the blend.
• "Null" Is Not an Error: If your chart shows "(null)" in some places, it’s not necessarily broken. With a left join, a null value just means there was no matching data in the second source. For example, a day with GA4 sessions but no ad spend would correctly show a null for the "Cost" metric, and that’s okay.

Final Thoughts

You now have a solid understanding of how to blend data in Looker Studio to create richer, more insightful reports. By mastering this feature, you can tell the full story behind your numbers by combining marketing funnel, cost, revenue, and behavioral data into a single, cohesive view.

While blending in Looker Studio is a fantastic step up from manual spreadsheet wrangling, it still involves some manual configuration, especially when managing multiple connectors and complex joins. At Graphed, we’ve automated this entire process. We allow you to connect all your marketing and sales sources with one click, and then use simple natural language - not configuration panels - to build dashboards. Just ask something like, “Show me my Facebook Ads spend vs Shopify revenue in a time series chart,” and our AI analyst builds the unified visualization for you, without you having to manually configure any join keys. If you want to create beautiful, cross-channel dashboards in seconds instead of hours, give Graphed a try.