TL;DR: Smart Bidding uses Google's AI to calculate the optimal bid at every auction. The five strategies — Maximize Conversions, Target CPA, Target ROAS, Maximize Clicks, and Target Impression Share — only work well when sufficient conversion data is available and targets are set realistically.
Which Smart Bidding strategies actually work in Google Ads — and when does manual bidding still make sense? Smart Bidding is not an autopilot but a powerful tool that requires the right configuration.
Quick Answer: Smart Bidding is the better choice for most campaigns — but only from at least 30–50 conversions per month. The most important strategies are Target CPA for lead generation and Target ROAS for e-commerce. Set your target 10–20% below your current average and improve incrementally.
What Is Smart Bidding?
Smart Bidding is Google's AI-powered bidding system. It analyzes – in real time, at every single auction – dozens of signals (device, location, time of day, search query, user history) and automatically adjusts the bid to achieve the stated goal.
This sounds like a set-it-and-forget-it solution – and in many cases, Smart Bidding genuinely outperforms manual bidding. But choosing the wrong strategy or implementing it too early can produce exactly the opposite effect.
The 5 Smart Bidding Strategies Compared
1. Maximize Conversions
What it does: Google sets bids to achieve as many conversions as possible within your budget.
When to use: When you primarily want volume and the cost per conversion is secondary. Good for the learning phase of new campaigns.
Risk: Without a budget cap, cost per conversion can vary significantly. Cheap but valueless micro-conversions can distort the system.
2. Target CPA (Cost per Acquisition)
What it does: Google optimizes to achieve conversions at your defined price. E.g., "I want to pay a maximum of €40 per inquiry."
When to use: Once you have at least 30–50 conversions per month. The AI needs sufficient data to optimize meaningfully.
Tip: Don't set the Target CPA too aggressively. If your current average CPA was €60, start with a target of €55 and reduce gradually.
3. Target ROAS (Return on Ad Spend)
What it does: Google optimizes to the return you define. At a Target ROAS of 400%, for every euro invested, €4 in revenue should be generated.
When to use: Ideal for e-commerce where you know the value of each conversion. Requires conversion value tracking (e.g., order value from your shop).
Prerequisite: At least 50–100 conversions with conversion values per month.
4. Maximize Clicks
What it does: Google tries to generate as many clicks as possible within the budget.
When to use: Very limited use cases – e.g., when you want to drive traffic to a new page and have no conversion data yet. Not suitable for profitable growth.
Warning: Clicks ≠ Conversions. This strategy can maximize cheap but completely irrelevant clicks.
5. Target Impression Share
What it does: Google bids so your ad appears in a certain percentage of possible auctions (e.g., 90% of the time at the top).
When to use: For brand awareness or ensuring your ad is always visible. Not cost-optimized.
When Is Manual Bidding Still Sensible?
Manual CPC bidding was long the standard – today it still has advantages in a few situations:
- Very few conversions: Under 15–20 conversions per month, Smart Bidding has no valid data foundation
- Excellent keyword segmentation: When you know very precisely which keywords have which value
- Small budgets: Under €200 per month, manual bidding can provide more control
In most other cases, Smart Bidding outperforms manual bidding – when the data foundation is solid.
The Learning Phase: Don't Disturb the Algorithm
When you activate or switch a Smart Bidding strategy, a learning phase of 1–2 weeks starts. During this time, Google tests various bidding approaches and collects data.
Important: Don't make fundamental campaign changes during the learning phase. No budget halving, no major keyword changes. This extends the learning phase and can reset optimization.
The Most Common Smart Bidding Mistake
Setting the Target CPA or Target ROAS too aggressively – then expecting Google to work miracles.
If your realistic cost per conversion is €80, you can't set a target of €20 and expect the system to work. Google simply won't place enough bids, traffic collapses, and the campaign delivers no results.
Rule: Set targets 10–20% below your current average – and improve incrementally.
Frequently Asked Questions
How many conversions do I need before switching to Smart Bidding? As a rule of thumb: at least 30 conversions per month for Target CPA, at least 50–100 for Target ROAS. Below that, the AI has too little data and behaves erratically. You can start earlier with Maximize Conversions, but keep the budget tightly capped.
What happens if I set the Target CPA too low? The system can't find enough auctions where it can meet the target. Impression share drops, traffic declines, and the campaign produces almost no results. Start with a realistic target and optimize step by step.
Can I mix Smart Bidding and manual bidding in the same campaign? No — a campaign always uses a single bidding strategy. However, you can use different strategies across different campaigns or ad groups.
How do I tell if Smart Bidding is working for my campaign? Compare cost per conversion, conversion volume, and ROAS over at least 4 weeks after the learning phase has ended, against your pre-Smart Bidding benchmarks. Short-term fluctuations during the learning phase are normal and not an indicator of poor performance.
Smart Bidding isn't an autopilot, but a powerful tool requiring the right configuration. With the wrong strategy it can burn your budget quickly. With the right one, it can significantly improve your efficiency. If you're unsure which strategy fits your current campaign data, we're happy to help with the analysis. Contact webflix.at for a free review.