Your Google Ads account reports 52 purchases this month. You open Shopify and see 41 orders attributed to Google. A spreadsheet you built from order exports shows 47 actual sales that came through paid search. Three different numbers, and none of them obviously right.
This situation is not rare. It is the default state for many Shopify stores that have been running Google Ads for more than a year, especially stores that have changed their theme, added or removed apps, or switched how they manage tracking.
This post explains the most common reasons the numbers are wrong, how to do a basic self-check without being technical, and why fixing this matters more than most owners realize.
Why Wrong Numbers Are a Bigger Problem Than a Reporting Headache
It is tempting to treat a tracking discrepancy as an accounting annoyance rather than a functional problem. It is not.
Google Ads uses its conversion data to operate its bidding algorithms. Target ROAS and Target CPA bidding, which most ecommerce accounts use, make real-time decisions about how much to bid on every auction based on the probability that the click leads to a conversion. Those probability estimates are built from the conversion history in your account.
If the account is recording two conversions per order instead of one, the algorithm believes your ads are twice as efficient as they actually are. It bids more aggressively. Costs rise. The ROAS in the account looks high because the conversion count is inflated, but actual revenue per dollar spent is lower than you think.
If the account is recording conversions without revenue values, a 25-dollar order and a 2,500-dollar order look identical. The algorithm sends traffic toward whatever produces conversions, not toward whatever produces revenue. A store with a wide product range could be spending most of its budget acquiring customers for its cheapest products.
If conversions are being undercounted, the algorithm cuts spend at exactly the moment it should hold or increase it, because the signal it is seeing is: this campaign is not working.
Wrong tracking does not just mislead you. It actively misdirects the ad spend.
The Most Common Problem: Counting Each Order Twice
The single most frequent tracking issue I find in Shopify stores is conversions being recorded more than once per order.
It usually happens like this. When the Google Ads account was first set up, the owner or their developer followed Google’s instructions and placed the Google Ads conversion tag directly on the Shopify thank-you page. Later, Google Tag Manager was added to the site for other tracking purposes. A GTM tag for Google Ads purchases was configured. Now there are two separate purchase tracking setups, both firing when an order completes. The account sees two conversions per order.
This can also happen when Enhanced Conversions (a newer tracking feature from Google) is enabled in two places: once through the Google Ads interface directly and once through a GTM tag. Or when a third-party attribution tool is installed alongside Google’s native tracking.
The account-level numbers look plausible because the duplication isn’t always exactly 2x. If some orders trigger both tags and some only trigger one, the inflation ratio varies. ROAS looks elevated. Nobody questions it because good-looking numbers get less scrutiny.
The way to check: take a two-week period, count the actual number of orders in your Shopify admin that came through any channel, then look at the purchase conversion action in Google Ads for the same period. If Google reports significantly more conversions than your actual order count across all channels, double-counting is likely.
Tracking That Breaks When Shopify Changes
Shopify’s checkout has changed substantially over the past several years, and each significant change creates a risk of tracking breaking silently.
The traditional approach to Shopify conversion tracking puts a tag on the order confirmation page (the thank-you page) that fires when a customer completes a purchase. This worked reliably for years. But Shopify has been migrating stores to a new checkout system called Checkout Extensibility, which changes how the thank-you page works. Stores that upgraded their checkout without updating their tracking setup often ended up with tags that fire inconsistently or not at all.
Other Shopify-specific breaking points I see regularly:
A theme update changes the structure of the thank-you page URL, and the tracking tag was configured with a URL-match rule that no longer applies.
A new checkout app replaces the default Shopify checkout entirely, and the conversion tag was placed in the original checkout flow, not the new one.
A store adds a post-purchase upsell app. Some customers now see an additional page after the original thank-you page, and the tag fires on both the original confirmation and the upsell confirmation page.
A store migrates from Shopify Basic to Shopify Plus and the checkout domain changes.
Any of these can break tracking without any error message or alert. From your perspective, orders keep coming in. From Google’s perspective, the conversion volume has dropped. The algorithm responds accordingly.
Not Passing Revenue Values
A conversion tracking setup can be technically firing correctly while still being meaningfully broken.
When a purchase event fires but does not include the order value (the amount the customer spent), Google records a conversion but without any revenue attached. The conversion count is accurate. The revenue data is missing.
This matters because ROAS, the metric that determines whether your campaigns are profitable, is calculated as revenue divided by spend. If revenue is not being passed correctly, the ROAS number you see in the account is either wrong (if a default value is being used) or zero (if no value is set at all).
A store running Target ROAS bidding with no revenue data is essentially flying blind. The algorithm cannot optimize toward profit because it has no idea what each conversion is worth.
This is straightforward to check: look at the Conversion Value column in your Google Ads account. If it shows zero or a flat placeholder number that never changes with your actual order sizes, the value is not being passed.
What Shopify’s Native Google Integration Does and Does Not Cover
Shopify has a built-in Google and YouTube app that connects Google Ads directly without requiring custom code. For a small store just starting out, this is a reasonable starting point. But it has real limitations.
The native integration uses Shopify’s own attribution model, which differs from how Google Ads attributes conversions natively. The result is that conversion counts and timing may differ between what Shopify shows and what appears in Google Ads, for reasons that are not straightforward to reconcile.
More importantly, Shopify’s native integration typically does not support Enhanced Conversions, which is Google’s method for recovering conversions that cookie-based tracking misses. On iOS devices, in browsers with strict privacy settings, and in any environment where cookies are blocked or expire quickly, a meaningful portion of conversions are simply not tracked at all without enhanced conversions in place.
The difference in practice: stores with properly implemented enhanced conversions typically see 15 to 30 percent more conversions recorded compared to the same store with basic cookie-based tracking only. That is not because more conversions happened. It is because more of the conversions that happened were captured.
What correct Shopify tracking looks like: conversion tracking configured through Google Tag Manager, with order revenue passed dynamically from the actual order data, with enhanced conversions enabled using first-party customer data, and with deduplication logic to prevent the same order from being counted by both a direct tag and a GTM tag.
A Non-Technical Self-Check
You do not need to understand the technical details to do a basic check on whether your tracking is likely to be accurate.
Pick a specific 30-day period. In your Shopify admin, look at the channel breakdown for that period and note how many orders are attributed to paid search or Google Ads. Then look at your Google Ads account for the same period and check the purchase conversion count.
These two numbers should be in the same ballpark. They will not be exactly equal because attribution models differ, but they should not be radically different.
If Google reports substantially more conversions than Shopify attributions, double-counting is likely. If Google reports far fewer, tracking is probably incomplete. If revenue values in Google Ads do not rise and fall with your actual revenue trends, revenue is not being passed correctly.
This check does not replace a proper technical review, but it tells you whether you have a problem worth investigating.
Getting This Fixed
Getting Shopify conversion tracking right is one of the most specific, highest-impact things I do before starting any campaign work for a store. Campaigns running on accurate data outperform identical campaigns running on wrong data, because the bidding algorithms are working from reality rather than noise.
If you suspect your numbers are off, or if you want to confirm they are correct before making budget decisions, I can help. Reach out at adnanagic.com/#contact.
Part of the Google Ads for Store Owners series, written for ecommerce owners who want their ad spend to actually work.
Related Posts
- Why Shopify Sales and Google Ads Sales Don’t Match
- Enhanced Conversions for Shopify: Setup Guide
- The Real Cost of Bad Conversion Tracking
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