The conversion window in Google Ads defines how far back the system looks from a click to attribute a conversion. If your conversion window is 30 days and a user clicks your ad then converts 45 days later, that conversion is not attributed to the ad. For AI Max campaigns, the conversion window directly affects the bidding model — the AI only learns from conversions it can see within the window.
Default Conversion Windows and Why They Matter
Google Ads default conversion windows:
- Clicks: 30 days (for most conversion types)
- Engaged-view conversions (video): 3 days
- View-through conversions: 1 day
These defaults work for e-commerce and short-consideration purchases. They're inadequate for B2B, SaaS, or high-value consumer products where the path from ad click to conversion can span 60-90 days.
In AI Max for Search, the bidding model uses within-window conversions as its feedback signal. A 30-day window means the AI never "sees" conversions that happen on day 31+. For B2B advertisers where sales cycles routinely extend beyond 30 days, this creates systematic undervaluation of AI Max performance — and potentially incorrect bidding.
The Maximum Conversion Window
Google Ads allows conversion windows up to 90 days for click-based conversions. For AI Max campaigns with long consideration cycles:
Set the conversion window to match your actual sales cycle. If your CRM data shows that 80% of deals close within 60 days of first ad contact, set a 60-day window. If 90 days is the realistic window for your segment, use 90 days.
For DSA campaigns migrating to AI Max for Search (https://yositeup.com/blog/google-ads-dsa-ai-max-migration-february-2027): check what conversion window your existing DSA conversion actions use before migration. If you used a short window with DSA and now migrate with a longer window in AI Max for Search, the apparent performance change may partly reflect the window change, not AI Max performance.
The June 2026 Deletion and Lookback Windows
The June 2026 data deletion (https://yositeup.com/blog/google-ads-reporting-data-deleted-june-2026) deleted reporting data for a specific pre-June period. Conversion windows interact with this deletion in a specific way:
If your conversion window is 90 days, conversions that occurred post-deletion but resulted from clicks before the deletion are affected. Specifically: clicks in late March/April/May 2026 that converted in June/July/August may be partially attributed to campaigns where the impression data was deleted.
This creates a measurement anomaly: the conversion exists (your CRM captured it) but the Google Ads attribution chain may be incomplete. For AI Max reporting purposes in summer 2026: treat conversion data from 60-90 day windows as potentially understated due to deletion-period attribution gaps. Use CRM-sourced conversion counts as the authoritative number for this period.
Micro-Conversion Lookback Windows
For long-consideration campaigns, micro-conversions (newsletter sign-ups, whitepaper downloads, webinar registrations) have shorter conversion windows than primary conversions (demo requests, purchases). Configure conversion windows per action:
- Primary conversion (purchase/demo/close): 90 days
- Lead form submission: 30 days
- Micro-conversion (content download, newsletter): 7-14 days
AI Max uses all active conversion actions as signals. Setting appropriate per-action windows means the AI sees micro-conversions quickly (useful for learning early in a campaign's life) while also learning from primary conversions over longer time horizons.
July 2026 ToS and Conversion Window Configuration
Under the July 2026 ToS (https://yositeup.com/blog/google-ads-tos-july-2026-ai-automation-what-changed), conversion window configuration remains the advertiser's responsibility, not the AI's. The AI optimizes within the window you set; it doesn't change the window.
This matters because the ToS's expanded AI authority is specifically for query selection, creative decisions, and bidding within configured parameters. Conversion window is a parameter the advertiser sets. Setting an inappropriate window (too short for your actual sales cycle) is an advertiser configuration error, not an AI decision.
For AI Max for Shopping (https://yositeup.com/blog/google-ai-max-shopping-replacing-performance-max-2026), most Shopping conversions are direct e-commerce purchases — shorter windows (7-30 days) are typically appropriate. For Shopping campaigns serving high-ticket items (furniture, appliances, electronics), extending to 60 days may capture more of the actual consideration cycle.
View-Through Conversions in AI Max: A Caution
View-through conversions (VTC) — conversions from users who saw but didn't click your ad — can inflate AI Max performance metrics. For AI Max for Shopping in particular, where Display placements are common, VTC counting can significantly inflate apparent ROAS.
Default: VTC window is 1 day. Consider setting it to 0 (disabling VTC) for AI Max campaigns where you want pure click-attribution reporting. VTC is useful as a signal but misleading as a primary performance metric — it attributes conversions that may have happened organically to ad impressions.
Under the July 2026 ToS, the AI Max bidding model uses a combination of click-attributed and view-attributed conversion data. If VTC is enabled, the AI includes it in bid calculations. Disabling VTC for bidding while keeping it for reporting insight (if the platform allows) is the cleanest approach.
Conversion Delay Reports: Useful After the Deletion
Google Ads provides a "Conversion lag" report (under Reports > Predefined Reports > Time > Days to Conversion). This shows the distribution of days between click and conversion for your account. Use it to:
- Verify your conversion window is capturing the vast majority of your conversions
- Understand how much of your AI Max performance is "delayed" — not yet visible in current data
- Post-deletion: understand how the deletion period intersects with your typical conversion delay
If your lag report shows 20% of conversions come after day 30, and you're using a 30-day window, you're missing 20% of conversions as AI Max learning signal. Extend the window.
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