An attribution window is the period of time after someone sees or clicks your ad during which a conversion is counted as being caused by that ad. If someone clicks your ad on Monday and buys on Friday, a 7-day click attribution window would credit that ad. A 1-day window would not.
The window you choose affects which ads look effective, how much budget you allocate, and which campaigns you scale. Two businesses running identical ads can see completely different ROAS numbers just because they chose different windows.
Click vs. view attribution windows
Most platforms let you set separate windows for clicks and views.
Click attribution windows measure the time after someone clicks your ad. Common options: 1 day, 7 days, 28 days, 30 days. A click is an intentional action, so most advertisers use longer click windows.
View-through attribution windows measure the time after someone sees your ad without clicking. Common options: 1 day, 7 days. View-through is more controversial because it gives credit to an ad the user may not have noticed or remembered. Most B2B advertisers use 1-day view-through at most.
Platform defaults and what they mean
Each ad platform has its own default attribution window, and they are not aligned:
- Google Ads defaults to 30-day click, 1-day engaged view, 1-day view-through for most conversion types.
- Meta Ads defaults to 7-day click, 1-day view.
- LinkedIn Ads defaults to 30-day click, 7-day view.
- Microsoft Ads defaults to 30-day click.
If you run Google and Meta simultaneously and use default windows, Google will take credit for a larger share of conversions than Meta for the same underlying behavior. Neither number is wrong, but they are not comparable.
How the wrong window distorts decisions
Too long a window overstates performance. A 30-day window on a campaign targeting quick decisions (emergency services, event tickets) will attribute conversions that happened weeks after ad exposure and were driven by something else entirely.
Too short a window understates performance. B2B sales cycles often run 60 to 90 days. A 7-day window on an enterprise software campaign will miss most of the conversions it actually influenced.
Mismatched windows make platforms compete for the same conversion. If Google has a 30-day click window and Meta has a 7-day click window, both may claim the same lead. Your total reported conversions can exceed your actual leads.
How to choose the right attribution window
Match the window to your actual sales cycle.
- Look at your CRM data. How many days pass between first ad click and closed deal? Pull the distribution, not just the average. If 80% of your deals close within 14 days of first touch, a 14-day window captures most of your actual pipeline.
- Consider the action you are measuring. If you measure form submissions, a 7-day window is usually reasonable. If you measure closed revenue, use a window that reflects your full sales cycle.
- Use the same window across platforms when comparing. Pick one standard (7-day click, 1-day view is common for B2B) and apply it everywhere so performance comparisons mean something.
- Set view-through conservatively. 1-day view-through is the industry standard for B2B. Longer view windows give credit to impressions that almost certainly did not drive the decision.
Attribution windows in Google Ads
In Google Ads, you set attribution windows at the conversion action level (Tools > Conversions > edit a conversion action > Attribution). Options vary by conversion type. For lead gen, you can choose 1, 7, or 30 days for click; 1 day for engaged view; 1 or 7 days for view-through.
Google’s data-driven attribution model distributes credit across touchpoints within your window. If a prospect clicked a branded search ad, then an awareness display ad, then a remarketing search ad, all three get fractional credit based on their actual contribution to conversion. This is more accurate than last-click within the same window.
Attribution windows in Meta Ads
Meta Ads Manager lets you change your attribution window in the Ads Manager settings (Columns > Customize Columns > Attribution Window). You can view performance under different windows without changing what is actually being optimized.
Meta’s default shifted from 28-day click to 7-day click in 2021 due to iOS 14 privacy changes. Many advertisers saw reported conversions drop; actual conversions did not change, only what Meta could track. The shift made their numbers more conservative but not necessarily more accurate, since iOS 14 limits pixel tracking.
Server-side tracking and attribution windows
Browser-based tracking (pixels, GA4 tags) increasingly misses conversions due to ad blockers, iOS restrictions, and cookie deprecation. Server-side conversion APIs send event data directly from your server to the ad platform, bypassing browser restrictions.
When you use server-side tracking via the Meta Conversions API or Google’s Enhanced Conversions, the attribution window logic stays the same, but you recover events that client-side pixels missed. This means your window settings start applying to a more complete dataset.
Comparing performance across windows
Before changing your attribution window, export performance data under the current window and save it. A window change reprocesses historical data, which can make campaigns that looked underperforming suddenly look strong, or vice versa. Without a saved baseline, you cannot tell whether a performance change is real or a measurement artifact.
Some platforms let you compare windows side by side. In Meta Ads Manager, you can add columns for 1-day click and 7-day click simultaneously. This shows you how sensitive your reported results are to the window setting.
Attribution windows and multi-touch attribution
If you use a multi-touch attribution model, the window determines which touchpoints are included in the path. A 7-day window only looks at touchpoints in the 7 days before conversion. If your buyer researched you 30 days ago, that first touchpoint is invisible.
For longer sales cycles, this is a real gap. First-touch attribution especially needs a window long enough to capture the actual first interaction, which may be weeks or months before the conversion event.
The practical answer for most B2B advertisers
Use 7-day click, 1-day view as your standard across all platforms. It is long enough to capture most B2B form submissions, short enough to avoid crediting unrelated events, and conservative enough on view-through to stay defensible. Apply it consistently so you can compare channel performance without window distortion.
For longer-cycle deals (enterprise SaaS, professional services), layer in a CRM attribution approach that tracks leads from first ad click to closed revenue regardless of window. Platforms only know what happens within their window; your CRM knows what actually closed.