The Looker Studio Sankey diagram is a powerful way to visualise flows between categories or dimensions. Unlike bar or pie charts, Sankey diagrams highlight how values move between nodes and show the relative importance of each path through link thickness.
In this tutorial, we’ll explore how to set up a Sankey diagram in Looker Studio, walk through an example using the H&M store dataset, and review the main customisation options.
👉 Visit the post on how to add charts to your report in Looker Studio, if you need a refresher.
What is a Looker Studio Sankey diagram?
A Looker Studio Sankey diagram shows how a dimension is distributed and flows into another dimension, making it easy to understand relationships and proportions.
- Nodes represent categories (e.g., continents, countries, cities).
- Links connect these nodes and vary in thickness depending on the metric’s value.
- Weight is defined by the selected metric, showing the scale of the relationship.
Sankey diagrams are particularly useful for:
- Tracking customer journeys across touchpoints.
- Analysing sales distribution by region or channel.
- Exploring hierarchical data flows such as Continent → Country → City.
How to create a Looker Studio Sankey diagram
You can insert a Sankey chart just like any other visualisation in Looker Studio:
- From the top menu, go to Insert → Sankey.
- Or, use the toolbar and click Add a chart → Sankey.
Step-by-step example: H&M stores dataset
In this example, we’ll visualise the relationship between Continent and Country using the number of H&M stores as the metric.
- Select Continent as the first dimension.
- Select Country as the second dimension.
- Set Record Count as the metric (number of stores).
The resulting Sankey chart displays links flowing from each continent to its countries, with thickness representing the number of stores.
Customising a Looker Studio Sankey diagram
Sankey diagrams come with chart-specific options that make them more readable.
1. Adjust row limit
- The default row limit is 500 rows.
- Reduce it to 20 rows to focus on the top-performing categories.
- This makes relationships much clearer and avoids clutter.
Here is our Sankey diagram with 20 rows, using Continent and Country as dimensions, and Record count as the weight metric.
The thickness of the link between the name of the continent and the country indicates the value of the metric (Record count). You’ll notice that Europe has more stores than North America, but if you look at it by city, the thickest link is from North America to the USA. The USA has the most H&M stores (532 in our dataset).
2. Change dimensions
- Try switching dimensions from Continent → Country to Country → City.
- This allows you to explore flows in more detail, such as which cities contribute most within a country.
In this example, all countries except China have a one-to-one relationship, where their capital or one of their major cities is in the top 20 with the most stores. China, aside from having Beijing in the top 20, also includes Shanghai, Guangzhou, and Shenzhen.
Why use a Looker Studio Sankey diagram?
The Looker Studio Sankey is ideal when you need to:
- Compare flows between two categories.
- Highlight scale of values through visual weight.
- Simplify complexity in hierarchical data.
For analysts and business users, it offers a fast way to identify where most of the “flow” or “volume” lies in a dataset.
FAQs about Looker Studio Sankey
Q1: What is a Looker Studio Sankey chart used for?
It shows how values flow between categories, with link thickness representing the magnitude of the relationship.
Q2: How do I create a Sankey in Looker Studio?
Insert → Sankey. Then select two dimensions and a metric as the weight.
Q3: Can I limit the number of rows?
Yes. By default, the chart allows 500 rows, but you can reduce this for clarity (e.g., top 20 values).
Q4: What are some use cases?
Customer journeys, regional store analysis, sales channel flows, or any dataset where values move from one category to another.
Key takeaways
- A Looker Studio Sankey diagram visualises flows between categories using node-to-node links.
- It is best for showing distribution, movement, and scale in a dataset.
- Use dimensions + metrics to define flows, and interpret link thickness as value weight.
- Customise row limits and dimensions to make relationships clearer.
- For official references, check Google Looker Studio documentation.
Sankey diagrams can turn complex datasets into clear, insightful visuals. Why not try building one with your own data and see what flows you uncover?
