How to Reduce Cost/Conversion on a New Maximize Conversions Campaign
I recently launched a consolidated Search campaign for one of our clients using the Maximise Conversions bidding strategy. It’s been running for about two weeks and has received 5 conversions so far. I created this campaign with only one primary conversion action (form submission), unlike the previous campaigns which were optimizing for multiple conversion actions. The goal here was to ensure that the entire budget is spent on the most valuable action.
Before this, the client had six different campaigns with their budget spread too thin, and they were using a clicks-based bidding strategy. Despite the limitations, those campaigns were delivering more conversions (the form submission ones)—the highest being 6 per campaign—at a much lower cost per conversion (ranging from $39 to $147).
In contrast, the new consolidated campaign has a cost/conversion of $680, which is significantly higher, and we’ve only received 5 conversions so far.
My objective is to bring down the cost per conversion while still achieving the same or better conversion volume as the previous campaigns. I’m currently evaluating two options:
Start a new campaign using Target CPA bidding strategy.
Create an experiment within the current campaign using Target CPA with a 70-30% budget split to test its effectiveness.
Would love to hear your thoughts on the best approach here. Has anyone faced a similar situation after consolidating campaigns and switching to Maximise Conversions? Would a switch to Target CPA help the algorithm optimize more efficiently, given the historical performance? Or should I give the current campaign more time to learn?
Thanks in advance!
The short answer is:
Your new Maximize Conversions campaign is struggling because you flipped too many switches at once (consolidation, new bidding strategy, and conversion action focus), which has starved the new machine learning model of the necessary historical, high-volume data signal.
You should create an experiment to test Target CPA (tCPA) with a 70-30% budget split, setting the initial tCPA just above the high end of your old average ($150-$170) to give the algorithm room to learn, and ensure the account-level conversion action history for the form submission is robust (ideally 30+ in the last 30 days) before launching.
The long answer is:
Your situation is completely normal when you make multiple, large changes simultaneously, especially moving from clicks-based bidding to Maximize Conversions.
The algorithm is essentially starting from scratch.
Your previous campaigns had their own historical data supporting the old bidding type, and that data didn’t translate perfectly to the new consolidated structure or the Maximize Conversions strategy, which is designed to spend the full budget to get the maximum number of conversions, regardless of cost, unless a target is set.
This is why your Cost/Conversion (CPA) is so high – the algorithm is bidding aggressively, testing the waters to find conversion opportunities and quickly spending the budget without any CPA constraint.
Your best move is to run the Target CPA experiment in the current campaign with the 70-30 split.
This is the low-risk approach, as it keeps the current campaign structure and data while introducing the necessary cost control.
Start with a relatively high Target CPA – try around $170 (slightly over the highest end of your old $39 to $147 range).
This gives the algorithm a generous runway to learn how to hit a lower cost target without severely limiting the auction opportunities, which is what would happen if you set it too low immediately.
You can then slowly and incrementally reduce this tCPA every two weeks as performance stabilizes.
Since Target CPA is now essentially Maximize Conversions with an optional target, this change will introduce the necessary guardrail to control cost while still leveraging the benefits of a consolidated structure.
The goal of ensuring the entire budget is spent on the most valuable action (form submission) is excellent, but for Smart Bidding to work, it needs a strong and consistent conversion signal.
The historical performance of your old campaigns is what you need to leverage.
You can also future-proof your conversion tracking and give the bidding algorithm a much more accurate and robust signal by implementing Enhanced Conversions.
An excellent and cost-effective way to do this is by leveraging the Google Ads API for server-side event tracking, managed through Google Tag Manager (GTM) and a server-side tagging environment like Stape or Google Cloud Platform.
Server-side tracking, hosted cheaply on a managed service like Stape, allows you to send conversion events directly from your server to Google Ads.
This process bypasses browser-side tracking restrictions like ad blockers and shortened cookie lifetimes, leading to a significant increase in conversion tracking accuracy.
Increased accuracy means more high-quality conversion data being fed back to the Maximize Conversions/Target CPA algorithm.
With a higher volume and better-quality data signal, the Smart Bidding algorithm can learn and optimize much faster and more efficiently, which directly translates to a lower Cost/Conversion and increased volume, giving you a competitive advantage that manual bid strategies can’t match.
Essentially, you’re improving the quality of the “fuel” the machine learning algorithm runs on.
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