Sometimes, our metrics in Looker Studio don’t have the data type or aggregation we want. In this post, I’ll explain how to modify both.
For the examples here, I’ll use the Superstore Products dataset.
1. Changing the Data Type
When creating a metric, it defaults to a number. In the examples where we created new calculated metrics, some should actually be displayed as currency. This can be easily modified by going to the list of fields in the data source (Resource → Manage added data sources → Edit data source).
Go to the row for the specific metric and select the dropdown under the Type column. There, you’ll see the option to convert it to a currency and select the specific one.

This can also be done for metrics you didn’t create yourself. For example, the Discount field might be a number, but it would make more sense as a percentage. You can change it in the same way.

This is also applicable to dimensions. For instance, if a City dimension is recognized as text, you might need to change it to geographic information. This is especially important when working with maps, as this visualisation type expects a geographic dimension.

2. Changing Metric Aggregation in Looker Studio
You may wonder why some fields, like Gross Revenue, are metrics but appear in green (dimensions). Revenue is a quantitative value and is undoubtedly a metric.
This change was introduced in an update to Looker Studio (previously Data Studio), where most fields were recognized as dimensions.
Note: This doesn’t happen with connectors like Google Analytics, where many fields are metrics. But it does occur with sources like Google Sheets, BigQuery, CSV, etc.
The advantage of this is that now you can change the aggregation of a field used as a metric directly within the chart, something that wasn’t possible before when the metric’s aggregation was predefined.
For example, when we created new metrics, one was Average Order Value. If you wanted to calculate it without creating a calculated field, you could do so by changing the aggregation of Gross Revenue to Average in your chart.
First, in the chart’s set-up, click on the text that appears on the left side of your metric (e.g., SUM).

To calculate the average order value, select Average as the aggregation type for gross revenue. This will give the average per row, meaning per transaction ID combined with product name.

It’s advisable to rename the metric when changing its aggregation (from Gross Revenue to Average Order Value). The original name of the metric can always be found under Source Field (Gross Revenue).
Once you rename the metric in the aggregation selection screen, the new name will appear in the chart configuration.

You can also do the same for calculating the number of customers by selecting Customer ID as the metric and Count Distinct as the aggregation.

Quick Tip:
- “Count” totals all IDs, including duplicates.
- “Count Distinct” counts unique IDs only.
3. Changing Comparison Calculation
Another helpful change you can make from within the chart is adjusting the comparison calculation. Besides showing total revenue by product category in a table, it might be interesting to know what percentage of total revenue each category represents.
To do this, add Gross Revenue as a another metric again, and under Comparison calculation, select Percent of total.


You might also want to know the difference in revenue between each category and the one with the highest sales. For this, choose Difference from total to see it as totals, or Percent difference from total to view it as percentages.


Ready to create and modify metrics? I hope so! But if you have any questions, feel free to leave a comment 🙂