Maximise Conversions is misunderstood - here is what it actually does
Maximise Conversions tells Google to spend your entire budget while getting as many conversions as possible. No target, no floor, no ceiling on CPA. That sounds reckless. In certain situations, it is exactly the right choice.
The reaction I often hear to Maximise Conversions is wariness. No CPA target means Google can spend freely chasing conversions at any cost, including very expensive ones. That concern is valid. But it misses the contexts where Maximise Conversions is genuinely the best tool.
When it works
New campaigns without conversion history are the primary use case. Target CPA and Target ROAS require data to work well. If you set a target on a brand new campaign, Google is guessing at what achievable looks like. Maximise Conversions lets the algorithm explore broadly, find conversions, and build the data it needs to support a constrained strategy later. Think of it as the learning phase strategy.
Limited-budget campaigns also benefit. If your daily budget is £30, setting a £25 Target CPA can result in the algorithm holding back spend waiting for high-probability conversions. Maximise Conversions on a small budget is often more aggressive and generates more actual volume.
Adding a target CPA cap
Maximise Conversions has an optional target CPA field. Adding a target converts it into Target CPA bidding while retaining the "maximise" framing. This is a useful middle ground - you get the exploration behaviour of Maximise Conversions while putting a ceiling on what you will pay per conversion. Start without the cap, build data for 30 days, then add a realistic target based on what you achieved.
The risk to manage
Without any target CPA, Maximise Conversions can produce very high-cost conversions in competitive markets. Monitor CPA daily in the first two weeks. If it is trending significantly above what is commercially viable, either add a target CPA cap or switch to Target CPA. Do not leave it running unchecked on large budgets without some form of cost constraint.
Maximise Conversion Value
The ecommerce equivalent is Maximise Conversion Value - optimises for total revenue rather than number of conversions. Same logic applies: useful during learning phases and in limited-budget scenarios. Add a Target ROAS once you have sufficient data and want to constrain the cost efficiency. The progression from unconstrained to constrained smart bidding is a strategy, not a fallback.
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