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Long Window, Short Tail: 90.4% of primary conversions came within a day of the ad interaction; on long-window actions, the median account’s share at 30 days or more was 0.5%.
Method basis: Doctor Ads Profit Forensics re-pull, 2 November 2026; days from ad interaction to conversion; unknown lag excluded.
Most accounts hold one long window. Most actions still sit on 30 days
Read the windows first, as any measurement review does. More than four in five accounts had at least one primary action longer than 30 days, and more than two in five primary actions sat on the 90-day click-through maximum. Most of the rest sat on 30 days, almost none shorter. For Search and Display, 30 days is Google’s default when nobody customises the click-through window.
90.4% of primary conversions with a known lag happened less than a day after the ad interaction, and 4.4% took 7 days or more.
On actions with windows longer than 30 days, among accounts with 30 or more conversions on them, the median account’s share at 30 days or more was 0.5%. All conversions on those actions together gave 3.9%: late conversions are concentrated in some accounts. There the long window matters; for the median account it barely does.
Check which group you are in, and what share of profit sits in late CRM sales, before changing bids or budgets.
Public studies are not directly comparable because their clocks differ
Google Ads counts from the ad interaction. Not every study below does.
Edgemesh, measuring its own analytics clients, timed a 2026 ecommerce panel from the first observed visit: 27.2% of revenue arrived more than 28 days later. It covers every traffic source. A later ad click restarts the Google clock, so it cannot show what a Google Ads window would miss.
Dreamdata, in a 2024 study of its own business-to-business customers, followed revenue from marketing touches in the first quarter of 2022. Only 37% came within that quarter, and it took six months for half of the revenue to arrive.
Northbeam described in 2026 one subscription food business measured from the click across channels. Moving from a 7-day to a 30-day window raised its attributed new-customer revenue by about 3.4%.
Maggie Humphrey of Cypress North described in 2026 a retailer that shortened its Google Ads click window from 30 to 7 days after an average lag of 2.2 days. Reported conversions rose 42.9%, but structure, budgets and bid strategies changed too, so the window’s effect cannot be isolated. She writes: “we can’t give all the credit to the shorter attribution window.”
What Google’s documentation does not provide. Google’s help offers rough guides, such as at least 7 days for Search and Display, but no delay curve by industry and no value for a long window’s last weeks.
What to check in your account
On a 30-day window, Google does not record later conversions, so its reports cannot show a late tail. Look for it in the CRM, matching sales to click dates through the click ID (GCLID).
- Read the window on every primary action. Go to Goals, Conversions, Summary; open each action your campaigns bid on, choose Edit settings and read the click-through and view-through windows. Search Engine Roundtable reports a new All conversions tab under Goals listing click-through windows, which may not reach every account yet. If attribution is set to Paid and organic channels, Google says changes must be made in Google Analytics.
- Run Days to conversion on mature clicks, old enough for their full window. In the Campaigns table, click Segment, Conversions, Days to conversion. Google’s instructions say the date range should end at least 30 days ago, longer for a longer window. For a split by primary action, with value beside count, ask the agency.
- Check upload deadlines in two places. Take click and deal dates from the CRM; read upload errors under Goals, Conversions, Uploads. Uploads made more than 90 days after the associated last click won’t be imported, nor 63 days for enhanced conversions for leads (import guidelines); a conversion older than the action’s window may also fail (troubleshooting). Engaged-view credit needs the upload within 14 days (engaged-view help). A longer window extends none of these.
- Date every window change. Record date, window and counting rule. Google applies a change only from that day forward, so compare periods only with matching settings, like the conversion mix behind a year-on-year report or counting one conversion per click versus every one. Reported cost per conversion shifts with the rule; for targets, Google’s Smart Bidding guidance allows one to two conversion cycles.
When this does not apply
Your window is already short. Google’s help says the Attribution time lag report, covering google.com interactions only, is capped at the window, as is Days to conversion. An empty tail proves nothing.
Your sales close over months. Then the tail may be material, as Dreamdata found; an advertiser on r/PPC describes purchases 4 to 5 months after the click. An expensive purchase may not close on the click day: in 2026 Big Flare’s Daryl Mander described one high-ticket online store with 33% of Google Ads conversions on the click date and 11.7% after more than 12 days.
You expect Smart Bidding to wait for the full window. Google says its bidding algorithms account for the length of your conversion cycle, weighing recent data less when the cycle is long.
When to ask for an independent check
If delay data, windows and CRM disagree, settle that first. Profit Forensics reads the lag of each primary action against the window set on it, before any bid or budget decision.
Researcher’s take
I would not choose a conversion window by habit. More data is no reason to keep the maximum, and a small median tail in our data is no reason to cut yours. Ask whether valuable sales arrive after the cutoff. If they do, keep the long window and keep late sales uploadable. The window decides which conversions Google counts; the sales ledger decides whether the business earned more.
Igor Ivitskiy, Doctor Ads Profit Forensics
FAQ
Should we set our conversion window to 30 or 90 days?
Decide from Days to conversion on mature clicks and CRM revenue by click date. Keep the longer window if a material share of value comes at 30 days or more.
Will a longer window recover sales we already missed?
No. Google says a change applies only to conversions recorded from that day forward.
Can Google Ads count a sale that closes after 90 days?
Not in standard conversion reporting today. Google says it keeps the GCLID for 90 days and recommends uploading a different offline event within that time, such as a qualified lead; keep the closed sale in the CRM.
Method
Data statement v.2026.11. Own source: a Google Ads API re-pull on 2 November 2026 of the accounts still reachable through our access; ad interactions from 1 November 2025 to 31 October 2026, the date Google Ads reports conversions against; enabled primary actions in accounts that spent in that year.
Google’s API describes the lag from the impression and its Days to conversion report from the click; for a search click the two are minutes apart, so at day resolution we read it as days after the ad interaction. Conversions with an unknown lag, 8.4% of primary conversions, were excluded. Pooled shares count all conversions together, so larger accounts weigh more. The median counts each account once, among accounts with 30 or more conversions on actions with windows over 30 days. Cost per acquisition was not calculated.
Limitations. The set is small. Windows were read on 2 November 2026, so earlier settings are unseen. The API returned no action source, so website actions, imported offline conversions and calls cannot be separated, and their mix may tilt the result. Recent interactions were not yet mature, which understates the tail slightly. Engaged-view windows were not measured. This is an observation, not a test.
Open sources: Edgemesh 2026 (25 stores and 1,214,190 checkouts, first visit); Dreamdata 2024 (own customers, size not stated, any touch); Northbeam, Cypress North and Big Flare 2026 (separate published cases, click). Google Ads Help checked 2 November 2026. Our percentages come from this Doctor Ads Profit Forensics re-pull; the others belong to the authors named.