Attribution window

An attribution window (also called a conversion window or lookback window) is the maximum time after an ad click or view during which a conversion, such as an app install, an order or a sign-up, is still credited to that ad. A conversion that happens after the window closes is not counted for that ad.

What is an attribution window?

Most platforms split windows into two types: a click-through window and a view-through window. The click-through window is usually longer, because clicking an ad signals more interest than scrolling past it.

Google Ads defines the conversion window as the period after an ad interaction during which conversions are recorded. Set it to 7 days and an order placed on day 8 will not appear in your reports. A change to the window only applies to conversions from that day on and does not recalculate past data (Google Ads Help, About conversion windows, accessed October 2026).

Default windows by platform

Sources: Meta Business Help Center, About attribution models and attribution settings, accessed October 2026; Apple Developer, Receiving ad attributions and postbacks, accessed October 2026; Adjust Help Center, Attribution windows, accessed October 2026.

GA4 has a similar setting called the lookback window for key events: 30 days for first_open and first_visit (can be changed to 7), and 90 days for all other events (30 or 60 are also available) (Google Analytics Help, Select attribution settings, accessed October 2026).

Since June 2025, AdAttributionKit has let apps set their own windows: 1 to 30 days for clicks and 1 to 7 days for views, applied to every ad network or set per network, plus a minimum cooldown between two conversions (Apple Developer, Configuring attribution rules for your app, accessed October 2026).

How to choose a window

Start from how long your customers really take to decide. Google suggests checking the time lag report in the Attribution section. If 75% of conversions happen between day 25 and day 30 after the interaction, the window has to be at least that long. When you compare two channels, give them the same window length. Otherwise the numbers cannot be compared.

Example

Hypothetical: an English language center runs ads to collect trial class sign-ups for a course that costs VND 12 million. CRM data shows that 40% of students pay more than 7 days after clicking the ad. With a 7-day window, close to half the revenue drops out of the ad reports and the campaign looks less profitable than it really is. A game app whose players make purchases within the first 24 hours is a different case: a 7-day window is plenty.

How it differs from similar concepts

Frequently asked questions

Is a longer window always better?

No. A long window credits ads for orders that customers would have placed anyway, without seeing the ad. To measure what your ads actually add, use incrementality testing.

Why do my MMP and Meta report different install numbers?

A common reason is that the two use different windows. Check the window settings in your MMP and in Ads Manager before deciding which side is reporting wrong.

If you want a second look at the attribution windows across your active ad accounts, you can reach Adtek through our contact page.