How Many Custom Dimensions Can You Create in a GA4 Property?

A standard Google Analytics 4 property supports 50 event-scoped custom dimensions, 25 user-scoped custom dimensions, and 10 item-scoped custom dimensions, according to Google's published GA4 property limits. Google Analytics 360 raises the event-scoped ceiling to 125 and the item-scoped ceiling to 25, while the user-scoped limit stays the same across both tiers.

Why the Limit Isn't Just "50"

Third-party summaries sometimes round this off to a single number, but GA4 actually tracks three separate limits by scope, and conflating them is a common mistake when planning a tracking implementation. Event-scoped dimensions — tied to a specific event, like a button label or a search term — get the largest allowance at 50. User-scoped dimensions, which persist across a user's sessions (such as a subscription tier or loyalty status), are capped lower at 25. Item-scoped dimensions, used specifically for e-commerce item parameters, get the smallest allowance at 10. A team that assumes it has "50 custom dimensions" to spend across all three categories will hit the user- or item-scoped ceiling well before using up their full budget.

Custom Metrics Are a Separate Limit

Custom metrics — numeric values rather than categorical dimensions — have their own limit that doesn't share a pool with custom dimensions. Planning a tracking schema that treats dimensions and metrics as competing for the same 50-slot budget will undercount how much room is actually available, since they're tracked independently by Google.

What Happens When You Hit the Ceiling

Google Analytics does let you archive a custom dimension to free up its slot for a new one, but archiving isn't free of cost: historical reporting tied to an archived dimension can stop functioning properly, since the dimension definition that powered those old reports is no longer active. There's also no retroactive backfill — a newly created custom dimension only populates with data going forward from the moment it's created, so a team that waits until hitting the limit to plan its dimension strategy has already lost historical visibility it can't recover.

The 360 Upgrade Changes the Math Meaningfully

For teams running into the standard property's event-scoped ceiling specifically, Google Analytics 360 roughly 2.5x's that allowance, from 50 to 125. That's a meaningful jump for large organizations with many product lines or complex event taxonomies, but it's a paid enterprise tier — not something available by simply requesting more slots on a standard property.

Bottom Line

Audit your GA4 property's custom dimension usage by scope — event, user, and item — separately rather than as one combined number, and build any new tracking plan against the 50/25/10 standard-property ceilings from the start so you're not forced into disruptive archiving later.

Sources: Google Analytics Help Center, "Google Analytics 360 (Google Analytics 4 properties)" limits documentation (support.google.com/analytics/answer/11202874); Google Analytics Help Center, custom dimensions and metrics reference (support.google.com/analytics/answer/9269570).