Calculate Percentages in Google Data Studio

Google’s data studio is great for basic reporting. To get the most out of it though, you’ll have to use some more advanced features. If you need a refresher on Data Studio, checkout the basics of Google Data Studio. The feature of today’s post is about calculating percentages.

There’s two broad categories to calculate percentages in Data Studio. The first is comparison calculations and the second is calculated fields.

Comparison Calculations

Comparison calculations are calculations using the base field as a comparison point. They can be found in the individual metric’s settings. Let’s say I want a chart that compares default channel grouping sessions and the corresponding percent of total sessions.

First, I’m going to add sessions to the metric field twice. In the second session metric, click on the settings or “pencil” for the field.

Once that opens, I’m going to rename the field, click on the comparison calculations drop down, and hover over “percent of total” -> “relative to corresponding data” or “relative to base data”.

The difference between corresponding data and base data can be tricky to initially visualize. This mostly matters when you’re doing a comparison of time frames.

Relative to corresponding data compares the percent change of the comparison calculation. Relative to base data compares the percent change of the original metric.

Notice that the second image below has the same % deltas.

Relative to corresponding data
Relative to base data

While there’s other options in comparison calculations, I’ve found percent of total to be the one I use most often.

Calculated Field

This is one of the features that Google has changed slightly since their Beta launch. You used to be able to click “Create New Field” below the available fields under “Available Fields”. Now the process is in a slightly different location. There’s two ways to use calculated fields. Chart specific calculated fields and data source calculated fields.

Chart Specific Calculated Fields

These are calculated fields that are only available on one chart. They have their upsides and downsides.


  • You don’t need edit access to the data source
  • You can create calculated fields with blended data


  • They are only valid on an individual chart level. Meaning that you’ll have to recreate them if you want to use them again.

Data Source Calculated Fields

These are calculated fields that are built on the data source.


  • The field is available on any chart or report that uses the data source


  • You must have edit rights to create the fields
  • You won’t be able to blend data between multiple data sources

Creating Data Source Calculated Fields

First, you’re going to want to edit the data source. The first option for doing this is going to your home page, clicking on “Data Sources”, then clicking on the data source that you want to add a calculated field to. Then click “Add A Field”.

Edit the Data Source

The second option is to go into the report you’re working on and click on “Edit Data Source”. Then click “Add A Field”.

Once you’re at the below screen, it’s time to create your new calculated field.

New User Ratio

The easiest example to build a new user ratio. This will give you an easy bar to measure if you’re actually driving new user acquisition as a percentage of your visitors as opposed to driving returning users back at a higher rate.

Now this metric will be available anywhere in your report. To build a calculated field that is only available to the chart, see below.

Creating Chart Specific Calculated Fields

Once you’re editing a chart, go to “Data”, and underneath “Metric”, select ” “Add Metric”. You should see the below. Click on “CREATE FIELD”.

Using the same formula or format as above, create your metric.

To be honest, I haven’t found too many uses for this feature. That’s probably because most of the data I use with Data Studio is fed from Google, Facebook, and other large tech players that have already pivoted the data every way that you’d need. Google has a full list of all functions that will most definitely be useful if you’re not using the same data sources that I am.

When I do find more uses, I’ll definitely be updating this post to let you know.

Once you’re finished building your metrics and dashboards, don’t forget to set the report up on a schedule to email your business stakeholders. This way, you set it and forget it but still get thought of every time the report goes out. Ahh true corporate politics at play…

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