Attribution window
Also called conversion window, attribution setting
An attribution window is the period after someone clicks or views an ad, or opens a marketing email, during which a purchase can still be credited to it. Meta, Google Ads, TikTok, GA4 and Klaviyo each set their own window, which is a big reason their combined sales add up to more than Shopify shows.
Sailesh B · Last updated
How it works
Someone clicks your Meta ad on Monday and buys on Thursday. Whether Meta counts that sale depends on its attribution window. With a 7-day click window, Thursday is inside it and Meta takes credit. With a 1-day click window, Meta doesn't.
Most platforms run more than one window at once:
- Click window: how long after a click a purchase counts.
- View window: how long after someone saw the ad without clicking. Usually much shorter, often one day.
- Open window (email): how long after someone opened a message. Klaviyo uses this; ad platforms don't.
A purchase only needs to fall inside one of them to be credited.
Default windows by platform
| Platform | Default window | What you can change |
|---|---|---|
| Meta Ads | 7-day click, 1-day view | Click 1 or 7 days; 1-day view on or off |
| Google Ads | 30-day click, 3-day engaged view, 1-day view-through | Click 1 to 90 days; engaged view and view-through 1 to 30 days |
| TikTok Ads | 7-day click, 1-day view | Click 1, 7, 14 or 28 days; view off, 1 or 7 days |
| GA4 | 30 days for acquisition key events, 90 days for all others | Acquisition 7 or 30 days; others 30, 60 or 90 days |
| Klaviyo (email) | 5 days after an open or a click | Window length, in account settings |
| Klaviyo (SMS) | 5 days after a click | Window length, in account settings |
| Shopify | No setting | Reports switch between models, not windows |
Sources: Google Ads, TikTok, GA4, Klaviyo. Meta has been changing its attribution settings during 2026, so check the options in your own Ads Manager before you rely on the Meta row.
Why it makes your reports disagree
Take one order. A shopper clicks a Google ad on day 1, clicks a Meta ad on day 20, opens a Klaviyo email on day 24, and buys on day 25.
- Google counts it. The click was 24 days earlier, inside its 30-day window.
- Meta counts it. The click was 5 days earlier, inside its 7-day window.
- Klaviyo counts it. The email was opened the day before.
- Shopify counts the order once and credits it according to the report's model.
If the shopper had only seen the Meta ad the evening before buying, Meta's 1-day view window would still claim the sale.
So three platforms each report the order as their own sale. Each one is applying its own rules correctly, and none of them knows what the others claimed. Add up every platform's revenue and you get more than your store took. Meta Ads not matching Shopify walks through the full gap.
It cuts the other way too. If your customers take two weeks to decide, a 7-day click window misses every sale after day 7, and the channel looks weaker than it is.
Which window should you use?
Two rules cover most stores.
- Match the window to how long your customers take to buy. An impulse product often sells the same day as the click. A sofa can take weeks. If many of your orders come more than a week after the first visit, a 7-day click window undercounts.
- Compare channels on the same terms. Meta on 7-day click against Google on 30-day click favours Google. Before you move budget between them, line them up on matching windows, or judge both against your Shopify orders.
Don't choose a window because it makes a channel look good.
Attribution window vs lookback window
The two terms are often used interchangeably. They describe the same gap, measured from opposite ends:
- An attribution window starts at the ad and counts forward: did a purchase happen within 7 days of this click?
- A lookback window starts at the purchase and counts back: which touches in the last 30 days get a share of the credit?
GA4 calls its setting a lookback window. Ad platforms call theirs attribution or conversion windows.
Does changing it change past numbers?
It depends on the tool:
- Google Ads and Microsoft Ads: no. A new window only applies to conversions from then on.
- GA4: a new lookback window only applies going forward. Switching the attribution model does recalculate past data.
- Klaviyo: yes. The new window is applied to historical data as well, which can take up to 36 hours.
- Meta: you can view past results under other windows with Compare attribution settings, without changing the ad set.
Write down the date you change a window. A jump in reported sales the following week may just be the new setting.
How this shows up in Shopify
Shopify has no window setting. Its marketing reports connect each order to the store visits Shopify recorded and assign credit with the model you choose (last non-direct click by default). Changing a window in Meta or Google never moves your Shopify numbers. And because Shopify counts each order once and never credits an ad view, its channel figures usually come in below what the ad platforms report.
How Prism handles it
Prism starts from each Shopify order and looks back up to 30 days for the store visits that came before it. Each order is counted once, with its credit split across the channels in its journey by the model you pick, so channel totals add up to your actual orders. An ad view with no visit doesn't count, because Prism only sees visits to your store.