The attribution window you pick decides which ad clicks get credit for a conversion. Set it wrong and Smart Bidding trains on noisy data. This guide shows you exactly how to pick and set the right window.
Quick answer: Run the Time Lag report. Match your window to where most of your conversions actually fall. The default 30-day window is rarely optimal.
What is an attribution window in Google Ads?
Definition and lookback period
An attribution window is the time frame Google looks back from a conversion to find the ad interactions that deserve credit. Per Google's Ads Help Center, it determines how far back in time ad interactions are eligible for attribution credit. Set it too short and you miss real touchpoints. Set it too long and you credit clicks that had nothing to do with the sale.
How attribution windows affect conversion tracking
Every conversion action in your account can have its own window. Google Ads records a conversion if the click happened within your set window. That data feeds your bidding algorithms, your reports, and every budget decision you make.
Click-through vs. view-through windows
Click-through windows (1–90 days)
Click-through windows track conversions after someone clicks your ad. Per Google's Ads Help Center, the default is 30 days. You can set it to 1, 7, 14, 30, 60, or 90 days. Most advertisers never change this default. That is usually a mistake.
View-through windows (1–30 days)
View-through windows track conversions from people who saw your ad but did not click. The maximum is 30 days. These matter most for display and video campaigns where impressions drive awareness. Keep view-through windows shorter than your click-through window to avoid double-counting credit.
Why attribution window matters for Smart Bidding
Accurate signal quality for bidding algorithms
Smart Bidding learns from your conversion data. A window that is too long feeds it noise. A window that matches your sales cycle feeds it signal. Research from Search Engine Land found that a client with a 2.2-day conversion cycle improved Smart Bidding performance and cross-channel reporting clarity after switching from 30 days to 7 days. Cleaner data. Better bids.
Avoiding noise from unrelated conversions
Long windows credit clicks that happened weeks before a purchase. Those clicks may have had no real influence on the sale. The noise inflates reported performance and makes bid optimization less accurate. Tighter windows give the algorithm a cleaner picture of what is actually working.
How to choose the right attribution window for your business
Using the Time Lag report to measure your sales cycle
Google Ads has a Time Lag report under Attribution. It shows the actual days between a user's first ad click and a conversion. Check it before you set any window. If most conversions happen within 7 days, there is no reason to use 30.
Setting windows for fast-cycle vs. long-cycle businesses
Fast-cycle businesses (ecommerce, impulse purchases) typically convert within 1–7 days. A 7-day or 14-day window works well. Long-cycle businesses (B2B, enterprise, high-consideration purchases) may need 60–90 days to capture the full journey.
Aligning with Google Analytics settings
Mismatched windows between Google Ads and Google Analytics create reporting gaps. If your Ads window is 30 days and your Analytics lookback is 90 days, the numbers will not agree. Pick a window, apply it consistently across both platforms, and review results against the same logic.
If you also run paid social on Meta, keeping your brand voice and creative identity consistent across channels matters just as much as consistent tracking. Coinis Brand Profile captures your brand voice and visual identity once. Every creative you build, across every channel, stays on-brand automatically.
Step-by-step: How to set your conversion window in Google Ads
Navigate to conversions settings
- Sign into Google Ads.
- Click the Goals icon in the left nav.
- Select Conversions, then Summary.
Edit conversion window for each conversion action
- Click the conversion action you want to edit.
- Click Edit settings.
- Find the Click-through conversion window field.
- Choose your window: 1, 7, 14, 30, 60, or 90 days.
- Click Save.
- Repeat for each conversion action. Google Ads lets you set independent windows per action.
Common attribution window mistakes
Setting 90 days by default without checking customer behavior
The 90-day window feels safe. It is not. For a business with a 3-day sales cycle, a 90-day window injects 87 days of noise. Your bidding then trains on conversions that were already decided long before the click that got the credit.
Misalignment between Google Ads and Analytics windows
This is one of the most common attribution errors. You see two different conversion numbers and spend hours trying to reconcile them. Align the windows first. The discrepancy usually resolves immediately.
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Frequently Asked Questions
What is the default attribution window in Google Ads?
The default click-through conversion window in Google Ads is 30 days. View-through windows default to 1 day. You can change these settings independently for each conversion action at any time.
How do I find the right attribution window for my business?
Run the Time Lag report in Google Ads under Goals > Attribution. It shows the number of days between a user's first ad interaction and a conversion. Match your window to where most of your conversions actually fall.
Can different conversion actions have different attribution windows?
Yes. Google Ads lets you set independent attribution windows per conversion action. A purchase conversion can use a 14-day window while a lead form submission uses 7 days.
Does changing my attribution window affect Smart Bidding?
Yes. Smart Bidding uses your conversion data to optimize bids. A tighter window that matches your sales cycle gives the algorithm cleaner signals and typically improves bid accuracy over time.