Custom Dimension

A user-defined attribute registered in an analytics tool, such as GA4, so a custom event parameter or user property can be reported on.

By Brandon MinaCEO, BrandPilot AIUpdated November 2026

Short answer

A custom dimension is a user-defined attribute registered in an analytics tool, such as Google Analytics 4, so that a custom event parameter or user property can be used in reports. Examples include author name, membership tier, or content type. Custom dimensions let teams analyze data by attributes specific to their business.