The most common cause is tag placement: a Google Ads conversion tag added through theme code never runs on Shopify's checkout or thank-you page, so purchases happen and Google Ads records nothing. The reliable setups are the official Google & YouTube app from the Shopify App Store or a purchase tag installed as a Customer Events pixel. Fix that first; then check consent mode and duplicate conversion actions, which are the next two causes on the list.
Here is the full checklist, ordered by probability.
Is the conversion tag actually on the purchase page?
Shopify's checkout ignores theme scripts. Anything you added by editing theme files stops at the cart. Two installs work:
- Google & YouTube app (Shopify App Store): links your store to Google Ads, creates the conversion action, and reports purchases including new-checkout stores. This is the default answer for most merchants.
- Customer Events pixel: in Shopify admin, Settings > Customer events > Add custom pixel, subscribe to
checkout_completed, and firegtagwith your conversion ID and label there.
To verify what is really firing, open your store in Chrome with Tag Assistant, complete a test order, and watch for the conversion event on the thank-you page. In Google Ads itself, go to Goals > Conversions > Summary, open your purchase action, and check its status column: "Recording conversions" is healthy, while "Inactive" or "No recent conversions" for a store with daily orders means the tag is not reaching the purchase page.
Are you counting every purchase twice?
Double counting is as damaging as zero counting, because Smart Bidding optimizes toward inflated numbers. It happens when two sources report the same purchase as primary: typically the Google & YouTube app's conversion action plus a GA4 "purchase" event imported into Google Ads.
Go to Goals > Conversions > Summary and look at your list. If you see two purchase-shaped actions both marked Primary (one sourced from "Website" and one from "Google Analytics 4"), pick one as Primary and set the other to Secondary. Secondary actions still record data but stay out of bidding and the main Conversions column.
Quick sanity check: compare a week of Google Ads conversions against Shopify orders from ads (in Shopify: Analytics > Reports, sessions by referrer). Google Ads slightly under Shopify is normal. Google Ads reporting more purchases than your store took is the double-count signature.
Is consent mode silently dropping your EU conversions?
Since March 2024, Google requires consent mode v2 signals for EEA traffic. If your cookie banner blocks ad_storage and never sends the consent update, Google discards those conversions instead of modeling them. Symptom: conversion counts fell off a cliff on the day you installed or changed a consent app, and EU campaigns look far worse than US ones.
What to check:
- Your consent platform (Cookiebot, Pandectes, Consentmo, or Shopify's own Settings > Customer privacy banner) advertises consent mode v2 support, and it is switched on.
- In Tag Assistant, load the storefront, accept the banner, and confirm a consent update with
ad_storage: grantedfires before the conversion tag. - In Google Ads, Goals > Conversions > Diagnostics flags consent problems per action; read it for your purchase action.
With consent mode implemented properly, Google models the conversions of visitors who decline, so you keep directional accuracy without tracking refusers.
Why do Google Ads and Shopify numbers never match exactly?
They are counting different things, so stop chasing a perfect match. The structural differences:
- Attribution: Google Ads credits a conversion to the click date and only counts orders with a
gclidclick ID inside the conversion window. Shopify counts every order on the order date regardless of source. - Tracking loss: Safari's ITP, iOS opt-outs, and ad blockers remove a slice of browser events. Enhanced conversions (hashed email matching) recovers part of it: turn it on in Goals > Conversions, open the action, and enable enhanced conversions with the Google & YouTube app as the source.
- Refunds and test orders: Shopify subtracts refunds from reports; Google Ads does not unless you upload adjustments.
A steady 10 to 25 percent gap with Shopify higher is the healthy range. A sudden change in the gap is the thing to investigate, because it usually means a tag died during a theme or app update.
What broke if conversions stopped on a specific date?
Pull up the conversion action's chart in Goals > Conversions and find the flatline date, then match it against what changed: a theme publish, a new app, a consent banner, or a checkout migration. Tags do not fade; they break on deploy days.
A free audit of your store shows every Google tag currently loading and whether the conversion fires on a real checkout run, which beats guessing from the theme editor. And because these breakages are invisible until the weekly ad review, scheduled checkout testing that also watches your pixels turns "why did ROAS crater three weeks ago" into an email the same morning it breaks.
FAQ
Why is my Google Ads conversion action showing "Inactive"? Google has not received that conversion event recently. Either the tag is missing from the purchase page (the usual case on Shopify), the site has genuinely had no conversions, or the tag fires with a different conversion ID and label than the action expects. Verify with Tag Assistant on a test purchase.
Should I use the GA4 purchase import or the Google Ads tag? Use the Google & YouTube app's native conversion (or a direct gtag) as Primary, and keep the GA4 import as Secondary if you want it for comparison. The direct tag reports faster and supports enhanced conversions cleanly.
How long do Google Ads conversions take to appear? Most report within a few hours; allow up to 24 for full attribution, and up to 3 days for conversions from consent-mode modeling. If nothing has appeared 24 hours after a verified test purchase, treat the setup as broken.
Do I need Google Tag Manager for Shopify conversion tracking? No. The Google & YouTube app or a Customer Events pixel covers standard purchase tracking. GTM on Shopify adds flexibility for complex setups but also adds one more place where a tag can be paused or overwritten by mistake.
Ad spend is only as good as the conversion data feeding it. Tracefox runs your real checkout on a schedule, confirms the order goes through, and monitors whether your Google tags actually fired on each run, so a dead conversion tag is an alert in your inbox instead of a mystery in next month's reporting.