An attribution window is the lookback period during which an ad click or impression gets credit for a downstream conversion. GA4’s default is 30 days for paid clicks, 1 day for organic. Google Ads has its own attribution-window settings (default 30 days). Cookie-based attribution windows shrink dramatically with ITP (7 days for first-party cookies on Safari, 1 day for third-party). Privacy-first tools generally don’t model multi-day attribution windows — they treat each session as standalone. If you depend on multi-touch attribution for marketing reporting, the migration is also a re-think of your attribution model — most teams shift to first-touch + last-touch reporting instead of GA4’s data-driven model.
Attribution window
The time period during which a click or impression is credited as the source of a conversion.