Google Ads
Google Ads and GA4 don't match. Which one is right?
Neither is wrong. Google Ads counts conversions using its own attribution model on its own ad clicks. GA4 counts conversions using a different model across every channel that sent you traffic, not just Google Ads. They're answering different questions, so a gap between them isn't a bug to chase down — it's the expected result of two systems built to measure differently.
Two systems, two definitions of "conversion"
A Google Ads conversion is scoped to Google Ads: it counts a purchase (or lead, or signup) that Google's own model credits to an ad click or view within that campaign's attribution window. GA4 doesn't work from clicks at all — it works from sessions, stitched together from whatever traffic source initiated them, and its purchase event fires the same way regardless of whether the customer arrived from a Google ad, an email link, organic search, or typed the URL directly. Compare Google Ads' number to GA4's total conversions and you're comparing a Google-Ads-only figure to an all-channels figure — they were never going to line up.
Different attribution models, different credit
Google Ads conversion tracking uses its own data-driven attribution model by default, applied only across a customer's interactions with Google Ads — search clicks, Shopping clicks, PMax touchpoints. GA4 runs its own data-driven model across the full channel mix it can see: paid, organic, social, email, direct. Even on an order that genuinely came from a Google Ads click, the two models can split credit differently if other channels touched the same customer journey. Google Ads has no visibility into the email click that happened two days earlier; GA4 does, and its model accounts for it.
Conversion date isn't the same date in both systems
Google Ads generally logs a conversion against the date of the interaction (the click), then applies a lag for when the conversion actually happened — so a purchase completed three days after the click can still show up on the click's date once the report settles. GA4 logs a purchase event against the session in which it occurred. Pull both reports on the same calendar day, especially a recent one still settling, and you're looking at numbers built on different date logic, not a discrepancy in what actually happened.
Consent modeling doesn't work identically either
When a customer declines cookie consent, both Google Ads and GA4 can statistically model conversions to fill the gap instead of just dropping the data — but they model against different consent signals (ad_storage for Google Ads, analytics_storage for GA4) and run separate modeling logic tuned to each product. A store with a meaningful share of consent-declined traffic can see Google Ads and GA4 diverge further than usual simply because each platform is filling in its own gaps differently, not because either one is measuring incorrectly. See Google Ads conversion tracking for Shopify for how Consent Mode factors into the Google Ads side specifically.
Cross-device journeys get stitched differently
Google Ads can connect a click on one device to a purchase on another when the customer is signed into a Google account across both — that's Google's own identity graph, invisible to anyone outside the platform. GA4 stitches cross-device behavior through Google Signals or a configured User-ID, which depends on your own site sending that signal and on the customer being logged in or otherwise identifiable to GA4 specifically. A phone-to-desktop purchase can get credited by one system and missed by the other, and there's no setting that reconciles the two identity graphs into one.
Three systems, three different questions
Google Ads answers "how many conversions is this ad spend credited with, by my own model, within my own window?" GA4 answers "how many purchase events happened in a session, attributed across every channel I can see?" Shopify answers a third question entirely: "how many orders were actually placed, for how much, net of refunds?" None of the three is lying. They're measuring different things, and the gap between any two of them is the size of that difference, not an error. The same logic applies to the Google Ads vs. Shopify comparison specifically — see why Google Ads and Shopify revenue don't match for the mechanics on that side, and ROAS tracking for Shopify for a fourth number — net ROAS — that's deliberately built to sit closer to Shopify's ledger than either ad platform's native reporting.
What's worth checking vs. what isn't
Don't spend time trying to force Google Ads and GA4 to the same total — structurally, they won't get there. Instead, track whether the ratio between them holds steady week to week. A stable ratio means both are measuring consistently, even if they disagree on the absolute number. A ratio that suddenly shifts — GA4 conversions holding flat while Google Ads drops, or the reverse — points at something that changed in one system specifically: a tag, a consent setting, or an import configuration, not a change in customer behavior.
Common questions
Which number should I report to my boss or client — Google Ads or GA4?
Can I make Google Ads and GA4 match exactly?
Should I import GA4 conversions into Google Ads to fix the mismatch?
Is a big gap between Google Ads and GA4 a sign something's broken?
Not sure which number your account should be optimizing on
Diagnosing a Google Ads vs. GA4 gap usually starts with a look inside both accounts. If the cause turns out to be a configuration issue that needs account-level access to fix, send an inquiry and we'll take it from there.