> For the complete documentation index, see [llms.txt](https://docs.whaly.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.whaly.io/data-visualisation/chart-your-data/retention-chart.md).
# Retention chart
Retention chart are a great way to visualize cohorts
### **Chart usage**
You must select two metrics to use the retention chart :
* The first metric is the cohort value, for example the retained users
* The second metric is the cohort size, for example the total number of users in a cohort
You should also select two dimensions to use the retention chart :
* The first dimension is the cohort label, this will be placed vertically
* The second dimension is the step in the cohort, the will be placed as a column
In order to have ordered dimensions you should provide alphabetically ordereable dimension values, for example :
Cohort labels:
```
2024-01, 2024-02, 2024-03, 2024-04, ...
```
Cohort steps:
```
Month 00, Month 01, Month 02, Month 03, ...
```
### **Chart characteristics**
* Number of metrics : 2
* Number of dimensions : 2
---
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