Good NumbersGoogle Ads usually double counts Shopify purchases because two purchase conversion actions are set as primary, often the Google and YouTube app's action plus a GA4 import or a GTM tag. Keep one primary purchase action, set the others to secondary, count it as Every conversion with the Shopify order ID as the transaction ID, and expect Smart Bidding to settle again within one to two weeks.
Google Ads says your Shopping campaign drove 260 purchases last month. Shopify says 310 orders came in from all channels combined, and Google was nowhere near most of them. When Google Ads reports conversions that look too good to be true, it is usually counting the same order more than once.
That matters more on Google than almost anywhere else, because Smart Bidding spends your budget based on those conversions. Double counted purchases make it bid for the wrong things. This guide shows how to find the duplicate in a few minutes and how to fix it without throwing your campaigns off.
Signs Google Ads is double counting
- Conversions close to, or above, Shopify orders from all sources, even though Google drives only part of your sales.
- Conversion value roughly double the revenue Shopify shows from Google traffic.
- A sudden ROAS jump after installing the Google and YouTube app, importing GA4 conversions or editing GTM.
- Average order value in Google Ads that doesn't match Shopify's, because some actions send different values.
How Google Ads counts purchases
Four settings decide what ends up in the Conversions column:
- Primary or secondary. Each conversion action is either primary, counted in Conversions and used for bidding, or secondary, shown only in All conversions. Every primary purchase action adds to the total.
- Count. Every counts each purchase after a click. One counts at most one per click. Purchases should use Every.
- Transaction ID. If two conversions for the same action have the same transaction ID, Google Ads only counts the first. This works within one action, not across two.
- Goals. Campaigns optimize toward account-default goals unless you set campaign-specific ones. The purchase goal contains every action in the Purchase category.
A transaction ID stops one action counting the same order twice. It does not stop two actions each counting it once. That's why most double counting survives even a correct transaction ID setup.
Find it in 5 minutes
- List your purchase actions. Go to Goals, Conversions, Summary. Open the Purchase goal and look at every action inside it. Note each one's source (website, Google Analytics, app) and whether it is primary.
- Count the primary ones. More than one primary purchase action on the same website is almost always the problem. Typical pairs are the Google and YouTube app's purchase action plus a GA4 import, or a GTM conversion tag plus the app.
- Segment by conversion action. In Campaigns, add the Conversions column, then Segment, Conversions, Conversion action. If two actions show similar numbers every day, they are recording the same orders.
- Compare with Shopify. Take orders whose source is Google in Shopify for the last 30 days. Google Ads should be in the same range, often a little higher because it credits clicks across devices. Close to double means duplicates.
- Check the settings of the one you'll keep. Count should be Every, and the action should receive a transaction ID. Tag Assistant shows it on a test order as the transaction ID in the conversion request.
The 4 usual causes
1. Two primary purchase actions
The big one. The Google and YouTube app creates its own conversion actions when you connect Google Ads. If the account already had a GTM purchase tag, or someone imported the GA4 purchase, both end up primary. Each order counts twice in Conversions and Smart Bidding sees double.
2. Missing or changing transaction IDs
Without a transaction ID, a purchase that fires twice in the same action counts twice. This happens when a tag fires on the order status page, which customers revisit. Make sure every purchase carries the Shopify order number or ID.
3. A GA4 import that already has duplicates
If GA4 itself counts orders twice, importing it brings the duplicates into Google Ads. Fix GA4 first. Our guide to GA4 duplicate purchases on Shopify covers how.
4. Leftover tags after a migration
After Shopify's checkout extensibility change, many stores rebuilt purchase tracking with a custom pixel and left the old action active, or installed the app on top of a GTM setup. Old and new both fire.
Our free tracking check compares Google Ads, GA4 and Meta purchases against your Shopify orders, finds every duplicate source and tells you which action to keep. Read-only, within 3 business days.
Get a free tracking checkFix it without upsetting Smart Bidding
- Choose one primary purchase action. For most Shopify stores, that's the Google Ads tag from the Google and YouTube app or a GTM conversion tag, with enhanced conversions turned on. It records conversions directly and uses Google Ads attribution.
- Set every other purchase action to secondary. Don't delete them yet. As secondary actions they stay visible in All conversions for comparison but stop affecting bidding.
- Confirm Count is Every and a transaction ID is sent on the primary action.
- Adjust ROAS and CPA targets. This is the step people miss. If purchases were counted twice, your real ROAS is about half of what you saw. A Target ROAS of 400% set on doubled data now asks for twice the real return, and Smart Bidding will cut spend sharply to chase it. Lower Target ROAS, or raise Target CPA, in line with the corrected numbers.
- Make the change on a quiet week and leave campaigns alone for one to two weeks while bidding settles.
If you're also unsure which ROAS number you should be comparing with, read how to find your true ROAS and work out your break-even ROAS before you set the new target.
Check it stays fixed
- Review conversion actions after every app install. Apps that touch checkout or marketing sometimes add their own Google Ads conversions.
- Watch Conversions against All conversions. A sudden gap means a new secondary action appeared, which is fine. A sudden jump in Conversions means a new primary one, which isn't.
- Compare with Shopify monthly. Google Ads purchases against Shopify orders from Google. The ratio should stay stable.
Duplicates rarely stay on one platform. The same app or GTM change that doubled Google Ads often doubles Meta too, so check Meta duplicate purchases while you're at it.
Common questions
Why does Google Ads show more conversions than my Shopify orders?
Usually because two purchase conversion actions are set as primary, so each order is counted once by each. The Google and YouTube app, a GA4 import and a GTM tag are the common combinations. A purchase firing on every order status page load is the other frequent cause.
What is the difference between primary and secondary conversion actions?
Primary actions are counted in the Conversions column and used by Smart Bidding. Secondary actions only appear in All conversions, for observation. Set one purchase action as primary and the rest as secondary.
Should I count purchases as One or Every?
Every. Count One records at most one conversion per ad click, which undercounts customers who buy again. Pair Every with a transaction ID so the same order is never counted twice by the same action.
Does a transaction ID stop duplicates across two conversion actions?
No. Google Ads deduplicates by transaction ID within the same conversion action. Two different actions recording the same order both count. The fix is having one primary action.
Should the GA4 import or the Google Ads tag be primary?
In most Shopify setups, the Google Ads tag, from the Google and YouTube app or a GTM conversion tag with enhanced conversions. Keep the GA4 import as secondary for comparison.
Freelance data and analytics engineer and founder of Good Numbers. Top Rated on Upwork. Specializes in GA4, Google Tag Manager, BigQuery, server-side tracking and Shopify attribution.