28-Day Click Attribution

A 28-day click attribution window counts a conversion that happens up to 28 days after someone clicked your ad. It is the longest click window named in Meta's announcement. Meta's developer announcement from October 2025 lists 28-day click among the windows that remain available for actions, conversions, and results, while saying that from January 12, 2026 the Ads Insights API would stop returning 7-day view and 28-day view. The announcement covers what the Insights API returns, so check your own Ads Manager to see which windows you can choose before planning around it. It is the widest click lens in that list, and it is most useful when a purchase involves research, comparison, or a partner's approval.

The logic is the same as other click windows: record the click, watch for a conversion from the same person, credit the click if it arrives in time. A longer window means more of the late buyers are counted, so reported conversions rise and cost per result falls, simply because you are catching more of them. Google Ads handles the idea with a configurable click-through conversion window. Google's help page says the default is 30 days, and the maximum is 30, 60, or 90 days depending on the conversion source. A longer window also means more overlap with other channels. Email, search, and direct visits can all happen in four weeks, and a click-based report will not show them.

The window interacts with your reporting rhythm. Results for any given click date keep growing for four weeks, so the last month's numbers are never final until the month after. It also interacts with other tools: GA4's reporting, your store's own analytics, and Meta will disagree more as the window grows, since more time lets other channels touch the customer in between. That is a reason to be careful about attributing a long-window sale to the click alone. Someone who clicked three weeks ago, then saw five other ads and searched your brand, was influenced by more than that click. That is why a long window is better as a diagnostic than as a scorecard. It tells you how much value your shorter windows leave out, not how much the click caused.

The common mistake is comparing a 28-day number to a 7-day number from another platform, then calling the gap a channel difference. Another is using a long window for a cheap product, where it adds noise rather than information, because the odds that a month-old click caused a $15 purchase are low. A third is optimizing on a window so long that your decisions arrive weeks late. You get cleaner measurement but slower learning, which hurts a small account with little time and money. If you decide to optimize on a long window, make sure the volume is high enough that the system gets enough events to learn from within a reasonable time. Keep this window for a quarterly review, not daily steering. It is a good way to see how much a long consideration cycle changes your picture, and then to choose a shorter day-to-day window that fits it.

Use 28-day click for high-consideration or high-ticket purchases where the sales cycle is long, such as mattresses, courses, or home services, and treat it as a reporting lens rather than a daily decision tool. This week, compare 28-day click against 7-day click for your last full month, which has now fully settled. If 28-day adds 5 percent more conversions, your customers decide quickly and the long window is not worth the delay. If it adds 40 percent, shorter windows are understating your results, and you should judge campaigns on the longer figure. Lock the numbers only after the window has fully elapsed, which means a month's results are not final until four weeks after the month ends.