A conversion window is the period after an ad interaction during which Google Ads credits a conversion to that interaction, helping measure campaign performance accurately.
A conversion window is the time period during which Google Ads waits after a click to attribute a conversion back to that click. If the conversion happens inside the window, Google credits the ad. If it happens after the window closes, the conversion is invisible to Google Ads, and Smart Bidding never learns from it. The window is set per conversion action.
Google's default conversion window is 30 days after the click. The maximum is 90 days.
[table]
Setting | Value | When to Use
Default | 30 days | Short-cycle transactions, most eCommerce
Maximum | 90 days | Standard B2B SaaS with 45-90 day cycles
Minimum | 1 day | Not recommended for B2B
[/table]
For B2B SaaS accounts, the 30-day default is almost always wrong. Sales cycles typically run 45 to 90 days from first click to closed-won. A 30-day window misses most of the pipeline that actually converts.
Take a B2B SaaS account with a 60-day average sales cycle. Let's say the conversion distribution looks like this:
With a 30-day conversion window, Google only sees the first 20% of conversions. The other 80% don’t get attributed to the click that started them.
This is why B2B SaaS accounts using the 30-day default systematically look worse than they are. Don’t get confused and blame the channel for being broken. Your measurement window is actually cutting it short.
Most B2B SaaS founders I speak to tell me they aren’t sure whether paid works. And when I ask them about their conversion window, nine times out of ten, it is set to 30 days, while their sales cycle is 60+. What’s actually happening is they are measuring the wrong number. Obviously, the conclusion will be far from reality.
I always recommend extending the conversion window to 90 days. And when they do, they come to me with the actual report.
Within 60 days of the change, reported CPA drops meaningfully. Reported conversion volume grows. ROAS lifts. Nothing about the campaigns themselves changes. It’s just that they understand what to measure and when.
For accounts wrestling with high CAC in Google Ads, the conversion window is one of the first things to check. Reported CAC that looks bad may just be reported CAC measured against a window too short to see the closed deals.
Set your conversion window based on your actual sales cycle, with a small buffer for lag.
[table]
Sales Cycle | Recommended Conversion Window
Under 30 days | 30 days (default)
30 to 60 days | 60 days
60 to 90 days | 90 days (maximum)
Over 90 days | 90 days + offline conversion import
[/table]
For accounts with sales cycles exceeding 90 days, the conversion window alone isn't enough. You need offline conversion tracking to import conversions that happen outside the window. OCI extends the effective attribution horizon by feeding events back to Google after the fact.
The wrong conversion window doesn't just misreport data. It corrupts Smart Bidding.
Smart Bidding optimizes toward conversions it can see. If the window only captures 20% of real conversions, the algorithm is training on 20% of the data. It builds patterns based on the small subset that converts fastest, not the full picture of who actually becomes a customer. The account starts finding low-quality, fast-converting leads and missing the long-cycle enterprise deals that make up most of the revenue.
For the full attribution picture that goes beyond conversion windows, our Google Ads attribution for B2B SaaS guide covers what to measure and why.
ScalixAI is a performance-driven Google Ads agency specializing in helping high-growth, AI-first companies scale with predictable, profitable customer acquisition. Founded by an ex-Googler with 9 years of insider advertising experience, we manage the entire Google Ads lifecycle—from campaign strategy and account setup to conversion tracking, analytics, and ongoing optimization. Our data-centric, AI-powered approach ensures you know exactly which campaigns are working, why they’re working, and what to do next to outpace your competitors.ScalixAI is a performance-driven Google Ads agency specializing in helping high-growth, AI-first companies scale with predictable, profitable customer acquisition. Founded by an ex-Googler with 9 years of insider advertising experience, we manage the entire Google Ads lifecycle—from campaign strategy and account setup to conversion tracking, analytics, and ongoing optimization.
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