> For the complete documentation index, see [llms.txt](https://help.littledata.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.littledata.io/google-analytics/conversions/conversion-rate-ga4.md).

# Conversion rate in Google Analytics 4

#### What is a Key Event?

Formerly known as conversions, GA4 "key events" reveal the actions that drive business success, offering insights into how users interact with your site or app.

#### Key Event Rate: Understanding the Metrics

GA4 introduced two types of key event rates (previously known as *session/user conversion rate*):

* **Session Key Event Rate**: The percentage of sessions that converted. This metric is calculated by dividing sessions with at least one key event by the total number of sessions.
* **User Key Event Rate:** Unlike the session key event rate, this measures the percentage of users who complete a key event at least once, regardless of how many sessions they have.

For example:

* Session Key Event Rate: If a user visits the site twice, with one of those visits leading to a key event, you have a 50% session key event rate.
* User Key Event Rate: If that same user completes a key event in one session, they’ll still be counted as a “converted” user even if they visit again without completing another key event

#### Session key event rate

The session key rate in Google Analytics is:

**Session Key Event Rate = (Number of Sessions with key events / Total Number of Sessions) x 100**

The session key event rate *won’t match* if you divide the number of key events by sessions because the formula is based on the number of sessions with key events. And **key events** will account for *all the events marked as key events.*

{% hint style="success" %}
The key event rate could be used in calculating the product conversion rate - how many users need to see a product before one of them decides to buy it?
{% endhint %}

For example, if a user triggered two key events in one session it will be counted as two key events, but will only be a single converted session.

{% embed url="<https://www.youtube.com/watch?v=Bs3rlH9Yc2M>" %}

#### Key Event Rate in Standard GA4 Reports

To see the session key event rate in your GA4 reports:

1.Go to Reports > Acquisition > Traffic Acquisition.

2.Click the pencil icon in the top-right corner to customize.

![](/files/sYGByWhdoWzkiqJjqgKw)

3.Under Metrics, add “Session Key Event Rate” to view it within your report.

![](/files/waM3pRUaJiqwxvzSR422)

The user key event rate can be added the same way and provides a user-based view of conversions rather than a session-based one.

{% hint style="success" %}
Make sure you select the **purchase** event in the dropdown under the session key event rate if you want to view the conversion rate for this particular event.
{% endhint %}

#### Creating a Custom Exploration in GA4

For more detailed insights, you can build a custom exploration to see how specific traffic sources and mediums influence your key event rate.

1.Navigate to Explore > Blank to create a new report.

2.Add Dimensions like “Session source/medium.”

3.Add Metrics such as “Sessions,” “Total users,” “Key events,” and “Session key event rate.”

![](/files/5w7kcUc3V7lx2xpkDzZ4)

1. Filter the data to focus on specific events, if needed (e.g., only “purchase” events). Filter pattern: **Event name** *matches regex* **session\_start|purchase**.

![](/files/OJszrjHDc1UJv9Bm8gfX)

This will ensure that only the *purchase* event is counted as the key event in the key event rate calculation.

**Summary**: Both the session and user key event rate metrics are essential in understanding your traffic sources, the performance of marketing campaigns and conversion actions.