Smart Bidding is the family of Google Ads automated bid strategies that use machine learning to set a bid in every auction, aiming for conversions or conversion value. It includes Maximize Conversions, Target CPA, Maximize Conversion Value, and Target ROAS.
Key Takeaways
- Smart Bidding sets the bid at auction time, for each search, rather than per keyword
- Two goals: more conversions (Maximize Conversions, optionally with a Target CPA) or more value (Maximize Conversion Value, optionally with a Target ROAS)
- It learns only from the conversions you track, so tracking quality sets its ceiling
- Strategy or target changes trigger a learning period
- Performance Max always runs on Smart Bidding
What Is Smart Bidding
With manual bidding you choose a maximum cost per click for each keyword. With Smart Bidding you choose a goal, and Google estimates for every auction how likely that click is to convert, and for how much, then bids accordingly.
| Strategy | Optimizes for | Optional target |
|---|---|---|
| Maximize Conversions | Number of conversions | Target CPA |
| Maximize Conversion Value | Total conversion value | Target ROAS |
How It Works
At each auction Google combines signals that a manual bidder cannot use one by one: device, location, time of day, language, browser, the exact search, and the audience lists the person belongs to. The model predicts conversion probability and value, and the bid follows. Only conversion actions set as primary feed the strategy; secondary actions are reported but ignored for bidding.
Practical Example
A lead-generation account tracks two actions: form submissions (primary) and visits to the contact page (also marked primary by mistake). Smart Bidding treats both as wins, and because page visits are far easier to get, it starts buying cheaper traffic that visits the page and never submits the form. Setting the page visit as secondary returns the strategy to the outcome the business cares about.
Why It Matters
Smart Bidding is only as good as the conversion actions it learns from. Broken tags, duplicated counts, or low-value actions marked as primary push bids in the wrong direction without any error message. Targets set too tight limit volume; targets set too loose spend more than needed.