Custom metrics in GA4 are numeric values you define and send with events — enabling quantitative analysis beyond GA4's default metrics like sessions and conversions.
Quick Answer
Custom metrics in GA4 are numeric values you define and send with events — enabling quantitative analysis beyond GA4's default metrics like sessions and conversions.
GA4 supports up to 50 custom metrics per property — use Currency unit type for any monetary values
Custom metrics are event-scoped only; there is no user-scoped metric type in GA4
Pair custom metrics with custom dimensions in Explorations to analyze quality (e.g., avg lead score by source)
Key Takeaways
GA4 supports up to 50 custom metrics per property — use Currency unit type for any monetary values
Custom metrics are event-scoped only; there is no user-scoped metric type in GA4
Pair custom metrics with custom dimensions in Explorations to analyze quality (e.g., avg lead score by source)
How Custom Metrics in GA4 Works
GA4 custom metrics extend the platform's measurement capability to business-specific numbers. They are always event-scoped — meaning the numeric value is attached to a specific event — and support three unit types: Standard (a plain number), Currency (formatted as monetary value), and Distance (meters). Each GA4 property supports up to 50 custom metrics. Like custom dimensions, custom metrics must be registered in Admin > Custom Definitions before they appear in reports, and data collection is non-retroactive.
Why Custom Metrics in GA4 Matters for B2B Marketing
For B2B analytics, powerful custom metric use cases include: lead_score (numeric MQL score from your marketing automation platform), estimated_deal_value (passed from CRM opportunity data), content_engagement_score (a composite of scroll depth + time on page + clicks), and form_completion_rate (step reached divided by total steps for multi-step forms). These metrics enable you to move beyond counting conversions and start analyzing conversion quality.
Custom Metrics in GA4: Best Practices & Strategic Application
Best practice: send custom metric values as integer or float parameters within your GTM event tags. Use the Currency unit type for any revenue-adjacent metric so GA4 formats it correctly in reports. Pair custom metrics with custom dimensions to create segmented analyses — for example, average lead_score by industry_vertical or by traffic_source. Build Exploration reports that use these metrics as primary KPIs rather than defaulting to session counts.
Agency Perspective: Custom Metrics in GA4 in Practice
A mistake teams make is sending text strings as custom metric values, which causes GA4 to reject or zero out the metric. Always validate numeric formatting in DebugView. Another error is using custom metrics for data that changes over time within a session (like a cart value that updates) — GA4 records the metric value at the moment of the event, so architecture your events to fire at the right moment in the user journey.
Frequently Asked Questions: Custom Metrics in GA4
Custom metrics in GA4 are numeric values you define and send with events — enabling quantitative analysis beyond GA4's default metrics like sessions and conversions.
Push the numeric value into the GTM data layer (e.g., dataLayer.push({'event': 'form_submit', 'lead_score': 78})). In GTM, create a Data Layer Variable to read that value, then include it as an event parameter in your GA4 Event tag. Finally, register it as a custom metric in GA4 Admin > Custom Definitions.
Custom metrics are raw numeric values you send via events (e.g., lead_score). Calculated metrics (available in GA4) are formulas you define within GA4 using existing metrics — for example, dividing total revenue by total sessions to create revenue_per_session. Calculated metrics require no additional data collection; custom metrics require implementation work.
Indirectly, yes. You can import GA4 key events into Google Ads and assign conversion values. If your custom metric represents a deal value or lead score, you can use it as the conversion value input, allowing Google's Smart Bidding algorithms to optimize for higher-value leads rather than just conversion volume.
MV3 Marketing helps B2B companies apply these strategies to drive measurable pipeline growth. Our team executes analytics setup for technology, SaaS, and professional services companies.
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24 hours
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