Google Analytics now lets you set custom attribution windows for each conversion, and the change quietly rewrites how you measure paid and organic performance. Until August 2026, GA4 boxed you in. You got a short list of preset lookback windows plus a fixed three-day window for engaged-view conversions. Now you pick any number of days that fits your real buying cycle. A 45-day B2B lead cycle no longer has to round down to 30 or up to 60. This guide covers what changed and the new day ranges. It also shows where to find custom attribution windows in GA4 and how to pick one that reflects how your customers actually buy.
Key takeaways
- GA4 replaced its preset lookback windows with custom attribution windows you set as any whole number of days.
- Click-through conversions now accept 1 to 90 days, and engaged-view conversions accept 1 to 30 days instead of a fixed 3.
- You set the windows under Advertising, then Conversion management, and can configure them per conversion.
- Conversion counts feed automated bidding, so a longer window raises reported conversions without proving extra sales.
- Google has not confirmed whether the new windows apply to historical data, so watch year-over-year comparisons.
What are attribution windows in GA4?
An attribution window, also called a lookback window, is the length of time GA4 looks backward from a conversion to decide which earlier touchpoints deserve credit. Say someone clicks a YouTube ad on day one and buys on day twelve. A 7-day window ignores that ad. A 30-day window credits it. The window sets the boundary of memory for your reporting.
GA4 tracks three touch types inside that window:
- Click-through conversions: the user clicked an ad, then converted.
- Engaged-view conversions: the user watched a meaningful portion of a video ad without clicking, then converted later.
- View-through conversions: the user saw an impression and converted without a click.
Choosing the right window matters because it decides how much credit upper-funnel work receives, the same problem we unpack in decision distance, the metric that tracks steps between discovery and action.
What changed with GA4 custom attribution windows?
Google rolled the update out in mid-August 2026 through the What’s new in Google Analytics release notes, with no separate blog post. The core change swaps rigid presets for free choice.
| Conversion type | Old setting | New setting |
|---|---|---|
| Click-through (CTC) | Presets only: 1, 7, 14, 30, 60, or 90 days | Any whole number from 1 to 90 days |
| Engaged-view (EVC) | Fixed at 3 days | Any whole number from 1 to 30 days |
The fixed three-day engaged-view window used to cut off any consideration period longer than 72 hours. That systematically undercounted video for slow-decision categories like furniture, insurance, and enterprise software. Removing the six-step click ladder also ends the forced rounding that pushed a 45-day cycle into a 30 or 60 day bucket. Google’s stated reason is simple: the change lets attribution windows align more closely with your unique business cycles.
Where do you set custom attribution windows?
You configure the new windows inside GA4 rather than in the Admin panel. Open Advertising, choose Conversion management, open the settings from the more options icon, and enter your click-through and engaged-view values. The same controls appear in the linked Google Ads conversion management interface, so the two platforms stay consistent.
Since a separate January 2026 update, these settings live at the conversion level, not just the property level. That means a newsletter signup and an ecommerce purchase in the same property can carry different windows. This matters, because those two actions rarely share a buying cycle. If your account leans on conversion-based bidding across newer ad surfaces, per-conversion control keeps each goal honest.
How do you choose the right attribution window?
Match the window to the length of your real sales cycle, not to a round number that feels safe. Two failure modes sit on either side:
- Windows that are too short under-credit long B2B lead cycles and high-consideration purchases, so channels that plant early interest look worthless.
- Windows that are too long over-credit distant touches in fast, impulse-driven sales, inflating the influence of ads that barely moved the buyer.
A practical starting point looks like this. A same-day ecommerce impulse buy fits a 7 to 14 day click window. A considered retail purchase fits 30 days. A professional services engagement can justify 60 to 90 days. Firms selling into high-value professional niches with long buying cycles almost always need the wider end. Pull your own average days-to-conversion from GA4 and set the window a little beyond it.
Why custom attribution windows matter for automated bidding
This is not just a reporting nicety. GA4 conversion counts feed Google’s automated bidding, so the window you pick changes how Smart Bidding spends. Lengthen a window and reported conversions climb, which can push the algorithm to bid more aggressively. Remember that the extra conversions often represent credit reassigned from another channel, not brand-new sales. Change windows deliberately, document the date, and expect a learning period while bidding recalibrates. Judge the shift by incremental revenue, the same discipline behind reporting the AI visibility metrics that actually reflect performance.
Attribution models still shape the credit
The window decides how far GA4 looks back, and the attribution model decides how it splits credit inside that window. GA4 defaults to data-driven attribution, which distributes credit based on observed patterns rather than a fixed rule. That model needs volume to work: at least 400 conversions for the specific key event and 20,000 total conversions across all key events. Accounts under that threshold fall back to a rules-based model such as last click. Set the window and the model together, because tuning one without the other still gives you a distorted picture.
Frequently asked questions
What is a conversion attribution window in GA4?
It is the period GA4 looks back from a conversion to assign credit to earlier ad clicks, engaged views, or impressions. Touchpoints outside the window get no credit for that conversion.
What is the default attribution window in Google Analytics?
Most conversions default to a 30-day lookback. With the new update you can raise or lower it to any value within the allowed range for each conversion type.
What is the difference between click-through and engaged-view conversions?
A click-through conversion follows an actual ad click. An engaged-view conversion follows a viewer watching a meaningful portion of a video ad without clicking, then converting within the window.
Do the new attribution windows apply to past data?
Google’s release note does not say whether the change is retroactive or forward-only. Until Google clarifies, treat pre-update and post-update reports with caution when comparing year over year.
Can I set different attribution windows for different conversions?
Yes. Since the early 2026 per-conversion update, each key event can carry its own window and model, so a lead form and a purchase in the same property can differ.
The bottom line
Custom attribution windows hand marketers a control they should have had years ago: the ability to measure a conversion over the time it truly takes to happen. Pull your average days-to-conversion. Set a window just past it for each key event, and pair it with a sensible model. Then watch how the change ripples into automated bidding. Judge everything by incremental revenue, not a bigger conversion number. For the official mechanics, see Google’s attribution and modeling documentation and PPC Land’s coverage of the engaged-view window change.
