Smart Bidding Requirements: What Google Really Asks For (and Which Numbers Are Wrong)

The two numbers that are not true as stated

Two rules of thumb have been circulating in agencies, forums and guides for years. Both can be refuted with Google's own Help pages. The pages were retrieved for this article on 30 October 2026; Google changes them from time to time, which is why every statement comes with its source.

Important for understanding: starting and evaluating are two different questions. Whether you are allowed to switch a strategy on is one thing. Whether you can judge after two weeks if it is working is another.

Target CPA: no minimum conversions to start

The Help page on Target CPA says, word for word:

"Advertisers can start using Target CPA with no conversion history."

The only hard prerequisite is conversion tracking that has been set up: "Before you can set up a Target CPA bid strategy, you'll need to set up conversion tracking to manage your conversion." (Google Ads Help: About Target CPA bidding, accessed 30 October 2026)

So where do the 30 conversions come from? They are on the same page, but in the context of evaluation: "For evaluation, we recommend you measure performance for the last 30 days, including at least 30 conversions." And elsewhere: "For more accurate results, it's recommended to measure performance over periods that have at least 30 conversions." That is a recommendation for reliable measurement, not an entry threshold.

Two further points from this page are relevant for small accounts:

• Target CPA is an average target. Google writes: "Some conversions may cost more than your target and some may cost less." Individual conversions can therefore become considerably more expensive.
• The daily budget is not a hard daily cap. According to Google, you should be comfortable "spending up to 2 times your average daily budget, while not exceeding the monthly charging limit".

If the campaign already has conversion data, Google recommends a Target CPA: the average CPA from the last 30 days, adjusted for any conversion delays. You can accept it or set your own value.

Target ROAS: real minimums per campaign type

Unlike Target CPA, Google states explicit requirements for Target ROAS. The Help page introduces them with the sentence: "To use Target ROAS bidding, the following requirements apply for different campaign types" (Google Ads Help: About Target ROAS bidding, accessed 30 October 2026).

The page does not state a minimum for Performance Max. Target ROAS also needs conversion values: without values, there is nothing on which the strategy could calculate a return.

Why Google still recommends 30 or 50 conversions for evaluation

The general Smart Bidding page combines both questions: "While you can turn on Smart Bidding without prior data, Google recommends meeting certain conversion baselines." On evaluation, it says: "To evaluate results accurately, Google Ads recommends measuring performance over longer time periods that have at least 30 conversions, such as a month or longer (50 conversions for Target ROAS)." (Google Ads Help: About Smart Bidding, accessed 30 October 2026)

Then there is the learning phase. After major structural changes, the strategy shows the status "Learning". According to Google, "you may see a 'Learning' status in your account for up to 7 days", your ads "continue to run and serve as normal", and "Smart Bidding performance typically converges to your new goal within 1 to 2 conversion cycles". Updates to budgets, ROI targets or targeting "never trigger 'Learning' status", according to the same page (Google Ads Help: About Smart Bidding learning, accessed 30 October 2026). Another Help page, by contrast, states a standard learning phase of 7 to 14 days and advises against frequent manual changes to budgets, targets and conversion goals during this time (Google Ads Help: About primary and secondary conversion actions, accessed 30 October 2026). The two pages do not fully agree. The careful approach is to bundle major changes and then wait at least one conversion cycle.

For an account with five enquiries a month, this means: switching it on is allowed, but a reliable assessment in line with Google's own recommendation takes several months.

Remarketing lists: 100 active users, with a documented contradiction

The Help page on data segments states the minimum size per network (Google Ads Help: How your data segments work, accessed 30 October 2026):

• Display Network: "a minimum of 100 active visitors or users within the last 30 days".
• Search Network: likewise a minimum of 100 active visitors or users within the last 30 days; customer lists have the same eligibility.
• YouTube: the same threshold of 100 in 30 days.
• Exception for customer lists: the 100-user requirement only applies to customer lists uploaded or refreshed after 1 February 2024. According to Google, older lists must still meet the previous requirement of a minimum of 1,000 matched users.

A second, older Help page on data segments for Search ads still contradicts this today. It says: "A segment that includes your website visitors or app users for Google Search ads needs to have a minimum number of 1,000 cookies before the segment can be used to tailor your Search ads." (Google Ads Help: About your data segments for Search ads, accessed 30 October 2026)

How should you deal with this? The page with the threshold of 100 is the more specific one: it states the requirements per network and explicitly classifies the 1,000 as the previous requirement for older customer lists. We therefore record: for the Search Network, Google today states 100 active users in 30 days, while an older page still states 1,000 cookies. If you are planning, you should know both values and check in your own account whether a segment is actually being served. Either way, 1,000 no longer works as a fixed rule.

What this means for small accounts

So the real bottleneck for small accounts is rarely eligibility, but the amount of data needed for an honest assessment and the lack of control over individual costs per click. How to assess bids without Smart Bidding, for example via impression share lost to rank and budget, is described in Reviewing bids and budget.

Checklist before you switch

1. Tracking active and primary. Only primary actions in the goal used for bidding feed into optimisation (Google Ads Help: About primary and secondary conversion actions, accessed 30 October 2026). How to check this is covered in Setting up and checking conversion tracking in Google Ads and in Primary and secondary conversion actions.
2. Suitable counting method. "One" counts only one conversion per ad click, "Every" counts every one. Changes only apply to future conversions (Google Ads Help: About conversion counting options, accessed 30 October 2026). For leads, "Every" quickly distorts the CPA.
3. Values set. For Target ROAS, every relevant action needs a conversion value.
4. Realistic timeframe. Work out how long your account takes to reach 30 conversions. That is roughly the time until a reliable assessment.
5. Watch the status. If the strategy shows "Learning", "Limited" or "Misconfigured (conversion setting)", do not evaluate yet (Google Ads Help: About bid strategy statuses, accessed 30 October 2026).
6. Hold steady after major changes. Bundle larger changes and wait at least one conversion cycle before you judge.

These points are part of areas 1 and 3 of the Google Ads audit checklist.

Where Helferlain stands on this

For changes, Helferlain only accepts bid strategies with a fixed cap: manual CPC bidding as well as "Maximize clicks" and "Percent CPC" with a maximum bid limit of no more than €10. Target CPA, Target ROAS and other strategies without a fixed cap cannot currently be set through Helferlain; you set those directly in Google Ads. A dedicated tool for this is planned. In the audit, "tracking first" applies: with 0 conversions, the tracking finding comes first, dependent findings are downgraded and there is no estimate in euros. More on the Google Ads audit page.