The problem
Most conversations about conversion tracking assume the danger is under-counting — a broken tag, a sale that never recorded, revenue you earned but cannot see. That happens often enough. But in a surprising number of accounts the problem runs the other way: the numbers are not too low, they are too high, because something is counting the same purchase more than once.
It usually happens quietly. Two different tags end up recording identical sales, and at some point someone marked both of them as important in Google Ads. Google then adds them together, reports the total in your headline figures, and optimises your bidding towards it. Nobody set out to inflate anything — the setup just drifted there, one integration at a time.
This matters on two fronts, and the second one tends to matter more. First, it feeds Smart Bidding a number that is too big, so the platform makes decisions on performance that was never real. Second, and arguably more serious, you may be reporting substantially inflated revenue back to your own business — telling the board, the client, or yourself that Google Ads delivered far more than it actually did. You can quietly correct a bidding problem. A credibility problem, once someone spots the gap between the ad platform and the bank account, is much harder to undo.
So it is worth five minutes to find out where you stand — either for the peace of mind that your numbers are right, or to catch a problem while it is still yours to fix. Just tread carefully if you find one: pull the wrong lever too quickly and you can knock your campaigns sideways, which is exactly why it pays to understand the whole picture before you change anything.
How the double-counting happens
In Google Ads, every conversion action is either a primary action or a secondary one. Primary actions are the ones that go into your headline “Conversions” column and, crucially, the ones Smart Bidding optimises towards, and the ones which are reported as sales and revenue. Secondary actions sit in the “All conversions” column for observation only — visible, but not driving anything.
Double-counting creeps in when two separate conversion actions both record the same sale and you have marked both as primary. Google has no way of knowing they represent the same underlying purchase, so it counts each of them. One real sale, two conversions, roughly double the revenue in the column that matters most.
The two usual causes are a platform integration that sets up its own tracking, and a GA4 purchase import running alongside a conversion tag you already had. Either on its own is fine. The trouble starts when both are live, both point at the purchase, and both are marked primary.
Shopify users especially
This one catches a lot of Shopify stores. When you connect the Google & YouTube app and link it to your Google Ads account, it automatically creates a set of conversion actions for you — and it sets Purchase as a primary action, ready for Smart Bidding, without asking. That is helpful if you had nothing set up before. But if you already had purchase tracking in place — a manual tag, a GA4 import, an older app — you now have two purchase actions, both primary, both counting every order. Nothing warns you. The reports simply start reading high.
It is not only Shopify. The Google for WooCommerce extension, the BigCommerce Ads & Listings app, and Google’s built-in setups for GoDaddy and PrestaShop can all create their own purchase conversion on top of one you already had. The specific app changes; the outcome is the same.
The five-minute check
You are looking for more than one primary conversion action that represents the same sale.
- In Google Ads, go to Goals > Conversions > Summary (in some accounts this still sits under Tools > Conversions).
- Select “view all conversion actions”
- Use the filter to filter by “Action Optimisation” and select ‘Primary’ on the filter
- Now you have your list of Primary Conversions. You are asking a simple question: is more than one of these recording a purchase or its revenue? Common tell-tale names are “Purchase”, “GA4 (web) Purchase”, a Shopify-created “Purchase”, and anything imported from Analytics.
- If you see two — or three — primary actions that all mean “someone bought something”, that is your double-count. Sense-check it by comparing the conversions each one reports over the same period; if two actions are recording near-identical numbers, they are almost certainly the same sale twice.
That is the diagnosis. It genuinely takes about five minutes, and it is one of those checks that either comes back clean or explains a lot at once.
And if you only have a single Primary Action recording your sales – It was worth the time to check for peace of mind.
What to do about it
There are two separate problems hiding in here, and they need very different handling. It is worth being clear about which is which before you change a thing.
The reporting problem
There are really two halves to this. The numbers you have already sent out to the business — last quarter’s board pack, the figures a client has already seen — you cannot un-say. There is no clean way to retro-correct what has already gone out, so the only honest move is to draw a line, explain that duplicate tracking inflated the figures, and report accurately from here. It is an uncomfortable conversation rather than a technical one, but it is far better had on your terms than discovered later.
What you can recover is a true picture of your own history. In Google Ads you can build a custom column that counts only the correct conversion action and ignores the duplicate, then apply it across any past date range — so you can see what your performance actually was, not the inflated version. That gives you accurate historical numbers to re-baseline your reporting against, and to take into that transparency conversation rather than a shrug. (We will cover how to build these custom columns properly in a separate tip — they are one of the most useful and least-used features in the account.)
This is not only about tidy reports, either. If the business has been making decisions on that inflated figure — signing off more budget for Google Ads because the return looked strong — then the bad number has quietly been steering where real money goes. A channel that appears to return £10 for every £1 spent, but is really returning £5, is a very different investment case, and the business may have been over-funding it for months on the strength of a number that was never true.
The bidding problem — handle this gently
The second problem is the one that needs care. If your campaigns have been optimising towards a doubled conversion figure, then simply switching the duplicate action to secondary will, overnight, appear to halve your performance. Smart Bidding will see conversions collapse and cost-per-conversion double, and it will pull back hard — not because anything really changed, but because you moved the goalposts without telling it.
So do not rip it out across the whole account at once. A measured approach is needed:
- First, find the truth. Segment a campaign’s report by Segment > Conversions > Conversion action to see how each action performs on its own, and work out your real CPA or ROAS on the single correct purchase action — not the combined figure.
- Then move in stages. Pick one lower-volume campaign, switch it to a campaign-specific conversion goal with the single correct purchase action as primary, and adjust its target at the same time — if your true conversion count is roughly half the old one, your tROAS or tCPA target has to move to match, or the algorithm will behave as though everything just got twice as expensive.
- Watch it settle, then roll the same change out gradually across the rest.
It’s very important to note here, that changing the data going into the bidding strategies can potentially have a disruptive impact while the bidd strategies go back into a learning phase. So do the above with utmost caution, and monitor the changes extremely closely. Be preared to act to adjust targets if volume spikes or drops away. We recommend doing this slowly with one campaign at a time.
The single most important point: whenever you cut the conversions Smart Bidding can see, move the target in the same breath. That one habit is the difference between a tidy correction and a fortnight of lost volume.
Which action to keep
If two purchase actions are reporting similar numbers, you only need one as primary — set the other to secondary so it stays visible for reference but stops feeding bidding. Which to keep is a genuine judgement call. We tend to keep the native Google Ads conversion, because its data lands faster and its click-based attribution suits bidding well. Either Google Ads or GA4 (or another source) is defensible — the one thing that is not is keeping both. You can read Google’s own guidance on primary and secondary actions here.
The bottom line
Run the check. Open your conversions, read the primary actions, and see whether more than one of them is counting the same sale.
If it is clean, that is five minutes well spent for peace of mind. If it is not, separate the two jobs: correct your reporting honestly going forward, and fix the bidding slowly and deliberately — one campaign at a time, always moving your target as you move your conversions.
Over-reporting is a quieter fault than a broken tag, because nothing looks wrong. The graphs go up and everyone is pleased. But a number that is too big is not a happier version of the truth — it is just a decision made on the wrong information, and in paid search that eventually costs you.