Why it happens
The attribution setting decides which purchases count for an ad. Meta credits a purchase to your ad only if it happened within a set number of days after someone clicked or viewed the ad. Meta's help lists settings such as 1-day click, 7-day click, and 7-day click or 1-day view. A longer window or an added view window lets in more purchases. A shorter one leaves some out. The setting sits on the ad set, so two ad sets can count by different rules.
Views and engaged views add purchases that clicks miss. A view window credits a purchase to someone who saw the ad and did not click. Meta also uses engaged-view attribution, which it now calls engage-through attribution in its news post. Meta's own news post from March 2026 says an engaged view of a video ad now takes 5 seconds instead of 10. The same post moves purchases after a share, a save or another click that is not a link click out of click-through and into engage-through. Meta says advertisers may notice changes in Ads Manager reporting, and that billing does not change.
Ads Manager and Events Manager count different things. Meta's help says Ads Manager counts only events it can tie to someone who saw your ad, after removing duplicates. Events Manager counts every event it received from your pixel and the Conversions API, attributed or not, before deduplication. The attribution setting changes the first number. It does not change what Events Manager received.
Ads Manager can date a purchase by the day of the ad. Meta's help describes Ads Manager reporting a conversion against the time of the click or impression that led to it. A purchase made today can then appear on the day the shopper saw the ad. Shopify dates the order by when it was paid. Change the window and some purchases also move between days.
Shopify counts every paid order. Your Shopify total includes buyers from search, e-mail and other ads. No attribution setting brings Meta's ad results up to your Shopify total, and a match on one setting does not mean the tracking is complete.
Check it yourself
- 1In Meta Ads Manager, open the ad set and read its attribution setting. Do the same for each ad set you add up, since they may differ.
- 2In Ads Manager, open Columns > Customize columns and add the comparing windows option for your purchase results. Meta then shows the same purchases under several windows side by side, without changing your ad set.
- 3Read the click and view numbers apart. If most of the difference sits in the view columns, the setting explains the change, and no purchases went missing.
- 4In Meta Events Manager > Data sources > your pixel > Overview, read the Purchase count for the same days. This is what Meta received. It stays the same whichever attribution setting you pick.
- 5In Shopify admin > Orders, filter by sales channel and keep the online store. Count paid orders for the last 7 full days, without point of sale sales, draft orders marked as paid and subscription renewals.
- 6Compare Shopify's paid online orders with the Events Manager count. That comparison tells you whether purchases reach Meta. If Events Manager is clearly below your orders, see Meta shows fewer purchases than Shopify.
- 7Compare whole weeks, and check that your ad account and your store use the same time zone. Recent days can still change as late purchases are credited to earlier ad views.
How purchases get to Meta in the first place is in setting up the Conversions API on Shopify.
FAQ
Which attribution setting is the right one?
Meta lets you choose per ad set. Pick one and keep it while you compare weeks. A count read under 7-day click or 1-day view cannot be compared with last month's count under 1-day click.
Do the comparing windows columns change my ad set?
No. They change only what you read in the report. The ad set keeps its own attribution setting.
Why did my purchases change when I changed nothing?
Meta's March 2026 changes to click-through and engaged-view attribution can move purchases between columns. Recent days also keep changing as late purchases come in. See Purchases show up days later in Meta Ads Manager or GA4.
Should Ads Manager match my Shopify orders?
No. Ads Manager counts purchases Meta ties to its ads under your setting. Shopify counts every paid order. Use Events Manager to check whether purchases arrive at all.