Smart Bidding: choosing your Google Ads bid strategy

What is Smart Bidding?

According to Google Ads Help on Smart Bidding, these strategies “use Google AI to optimize for conversions or conversion value in each and every auction”. Google calls this mechanism “auction-time bidding”.

Smart Bidding is a subset of automated bidding. “Maximize clicks”, for example, is automated. But this strategy targets clicks, not conversions: it is not Smart Bidding.

What are the Smart Bidding strategies?

Four strategies, two families: those that count conversions and those that measure their value.

Strategy	What it aims for	When to choose it
Maximize conversions	As many conversions as possible within the budget	Launch, volume goal, no reference CPA yet
Target CPA	As many conversions as possible at the target average cost per acquisition	Lead generation with a controlled acquisition cost
Maximize conversion value	The highest total value within the budget	E-commerce or valued leads, with no set profitability target
Target ROAS	The target value for each euro spent	E-commerce with an advertising profitability goal

A poorly set target is expensive. Google warns that a Target CPA set too low makes you give up clicks that could have converted. Total conversions then drop. Conversely, a Target ROAS set too high may limit traffic. Start from your actual results, then adjust in steps.

Enhanced CPC (eCPC) adjusted a manual bid. It has no longer been available for Search and Display campaigns since the end of March 2025. Campaigns that were not migrated switched to manual CPC.

How does Smart Bidding set bids?

For each search, the algorithm estimates the likelihood of conversion from signals, alone or combined. Google lists several in its documentation:

• the device (mobile, desktop, tablet) and the operating system;
• the location, down to the city, even if your targeting is broader;
• the day and time;
• remarketing lists and the history of interaction with your site;
• the actual search query, not just the keyword that triggered the ad;
• seasonality and, for Shopping, product attributes.

Some of these signals are not available with manual bidding. This is Google’s main argument: a bid recalculated for each search. Smart Bidding is used in Search, in Shopping and in Performance Max, which has no other bidding mode. The other formats are described in our page on Google Ads campaigns.

What are the prerequisites before switching to Smart Bidding?

Smart Bidding optimizes what you measure. A poorly defined conversion, or one counted twice, produces wrong bids. Google makes conversion tracking mandatory. It recommends judging performance over a month or more, with at least 30 conversions, or 50 for Target ROAS.

1. Audit conversions: one primary conversion per business goal, with no duplicates and the right attribution window.
2. Pass values: real revenue in e-commerce, estimated value per lead type in B2B.
3. Check volume: is a campaign far from 30 conversions a month? Group campaigns together or start with “Maximize conversions”.
4. Set a realistic target: start from the CPA or ROAS observed over the last few weeks.
5. Test: use an experiment campaign to compare the new strategy with the old one on part of the traffic.

Measurement quality is settled before any bidding question. It depends on your web analytics tool and on how Google Ads conversions are set up.

How do you handle the learning period?

After a strategy is created or changed, Google displays a “Learning” status. This period can last up to 50 conversions or three conversion cycles. It is shorter if the history is rich (Google Ads Help on the learning period). Manual CPC, for its part, has no learning period. It is triggered in particular by:

• creating or reactivating a strategy;
• changing its settings, including the target;
• adding or removing campaigns, ad groups or keywords.

For a short promotion, Google offers seasonality adjustments. You announce an expected rise in conversion rate; the algorithm anticipates it. Google reserves them for short events, from one to seven days. Smart Bidding already handles usual seasonality on its own.

Smart Bidding or manual bidding: which should you choose?

Smart Bidding suits most accounts that measure reliable conversions in sufficient volume. Manual bidding still makes sense in three cases:

• very few conversions;
• a need for fine control over the bid of a specific keyword;
• a test phase where you want to isolate the effect of an ad.

In 2025, Google launched an option to broaden the reach of Smart Bidding:

This figure comes from Google, which sells the inventory. It shows a trend, not a guaranteed result on your account. On the Search side, ad quality and keyword choice remain your levers. The bid strategy changes nothing there.