Custom dimensions and metrics

A note about scope

"Event scope" was previously referred to as "Hit scope" in Universal Analytics (UA).
  • User scoped custom dimensions are coming soon.
  • Session and item scopes are on the roadmap for 2021.

Event-scoped custom dimensions and metrics take their values from the event parameters you collect via the Analytics measurement code. Automatically collected events have some default parameters, and you can specify up to 25 custom parameters per event (Android or iOS).

During the creation process, you identify the event parameter that will supply the value for the custom dimension or metric.

Create a custom dimension or metric

You need Edit permission to create custom dimensions and metrics.

  1. Sign in to Google Analytics.
  2. Select Reporting Down Arrow in the top of the left pane.
  3. Click All events, under EVENTS.
  4. Click Manage Custom Definitions.
  5. Click Create custom dimensions.

    (To create a custom metric, click Custom metrics > Create custom metrics.)
  6. Choose a parameter from the list of collected parameters in the Event parameter name field, or
    1. Option 1: Enter the name of the parameter that will provide the value for the custom dimension or metric.
    2. Option 2: Enter a new name for a parameter you will collect in the future.
  7. (Custom metrics) In the Unit of measurement field, select the appropriate unit of measurement for the custom metric.
  8. In the Custom dimension name or Custom metric name field, enter a unique name. This is the name that will be displayed throughout reports so use a descriptive name.
  9. Click Save.
NOTE: You may see a value of "not set" for a custom dimension during the first 24 hours.


  1. In the left pane, click All events.
  2. In the row for the dimension or metric, click and then, then click Edit.
  3. Make the changes you want, then click Save.


If you need to create new custom dimensions and/or metrics but you have reached your limit of 50 in either case, you can archive ones you are no longer using in order to free up quota.

  1. In the left pane, click All events.
  2. Click Manage Custom Definitions.
  3. Open either the Custom dimensions or Custom metrics tab.
  4. In the row for the dimension or metric, click More > Archive.

Custom counter

GA4 property users can create up to 50 custom dimensions and 50 custom metrics per property.

The total number of custom dimensions and metrics you've created appears at the bottom of the list. When you reach the quota of 100 (50 dimensions and 50 metrics), the number will turn red, indicating that you can't any more create custom dimensions and metrics.

Custom parameter reporting

Event-scoped custom dimensions and metrics (GA4) replace Custom parameter reporting (UA).

With event-scoped custom dimensions and metrics, parameters are identified for property-wide dimensions and metrics, allowing you to create a single dimension or metric based on a parameter and report on it for as many events as you wish. Previously with custom-parameter reporting, parameters were identified for individual events. Consequently, if you wanted to report on the same parameter for five different events, you had to use five of your 100 limit.

With the deprecation of custom-parameter reporting, Analytics has preserved historical event-scoped aggregates, and new aggregates seamlessly extend that historical data. In cases where a parameter was registered for multiple events, Analytics disambiguates between them by assigning a dimension/metric name that includes the currently assigned event name (e.g., “custom_dimension_name [event_name]”). As a best practice, you should remove duplicate custom dimensions and metrics that were registered across multiple events to help preserve quota.

If you have reached your quota but need to create new custom dimensions and/or metrics, you can archive the ones you are no longer using.

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