Why N-Day retention?

It tells you what % of users come back exactly N days after signup. It’s the ultimate stress test of product stickiness—do people return when they’re “supposed to”?

What breaks the calculation?

• GA4 reports simplify into broad cohorts
• N-day granularity isn’t exposed in UI
• Raw exports need manual alignment of first and return dates

How to solve with SQL?

• Anchor each user at their first activity date
• Use DATE_DIFF to measure gaps between first activity and later events
• Flag users who return on day N

What’s the takeaway?

N-Day retention curves built directly in BigQuery. No BI overhead, no guesswork—just raw proof of how sticky your product really is.

Want all my best GA4-BQ queries in one place? I turned them into a Chrome extension — top SQL queries you can search and copy in seconds.

Go here to install it for FREE.

Prefer the web version? It's here.