Google Ads bidding strategies: how to choose, what data each needs, and the learning period

Google Ads bidding strategies fall into two groups: manual bidding, where you set the maximum cost per click yourself, and automated bidding, where Google sets a bid for every auction based on a goal you choose (clicks, impression share, conversions or conversion value). The right one depends less on preference and more on what your account can measure: a campaign with reliable conversion tracking and steady conversion volume can hand bids to Smart Bidding, while a campaign with no tracking or very few conversions is better served by Manual CPC or Maximize clicks until the data exists.

This guide walks through each strategy available for Search campaigns in 2026, what data each one needs, how to tell when it is time to switch, and what actually happens during the learning period. It also covers the August 2026 change to how target-based strategies behave on budget-limited campaigns, because that change affects anyone still using an aggressive target as a spending brake.

The Google Ads bidding strategies available for Search campaigns

Google's own list for Search campaigns currently contains seven options. Some accounts see Target CPA and Target ROAS as standalone entries in the strategy menu, while others still reach them as optional targets inside Maximize conversions and Maximize conversion value. Either way, the bidding behaviour is the same.

Manual CPC

You set a maximum cost per click at the ad group or keyword level, and Google never bids above it. You can still add bid adjustments for device, location and ad schedule. Manual CPC gives full control and full responsibility: every bid change is yours to make, and nothing adapts to the individual searcher. Enhanced CPC, the semi-automated layer that used to sit on top of Manual CPC, has not been available for Search and Display campaigns since the week of 31 March 2025. Campaigns that were still on it now run on plain Manual CPC.

Maximize clicks

Google sets bids to get as many clicks as possible within your daily budget. You can add a maximum CPC bid limit so a single click never costs more than you are comfortable paying. It optimises for traffic volume, not traffic quality, so it suits new campaigns that need data quickly, but it will happily buy cheap clicks that never convert.

Target impression share

You pick where the ad should appear (absolute top of the page, top of the page, or anywhere on the page) and the percentage of eligible auctions in which it should appear there. This is a visibility strategy. It is useful on brand terms, where showing up first matters more than cost per lead, and risky on broad generic terms, where chasing a high share can push CPCs up fast. Setting a maximum CPC bid limit is strongly advisable here.

Maximize conversions and Target CPA

Maximize conversions spends the full daily budget trying to get the highest number of conversions. Adding a Target CPA tells it to aim for an average cost per acquisition instead, which usually means fewer conversions at a steadier cost. Both use Smart Bidding, which means Google evaluates signals at auction time (device, location, time of day, language, the query itself and more) and sets a bid for that one auction. Both count only the conversion actions included in your "Conversions" column, so what you mark as a primary conversion is literally what the system chases.

Maximize conversion value and Target ROAS

The value-based pair works the same way but optimises for the total conversion value rather than the conversion count. Target ROAS asks for an average return on ad spend, for example 400 percent meaning four baht of tracked value for every baht spent. Google's requirement for value-based bidding is that your conversion goals report two or more unique values, which can be real economic values such as revenue or proxy values such as a lead score. If every lead is recorded with the same value, a value strategy has nothing to tell apart and behaves like a conversion-count strategy with extra steps.

Outside Search, a few campaign types have their own options. Target CPC exists only for Demand Gen, and Pay for Conversions appears only for eligible Display campaigns, so neither is covered here.

Manual CPC vs Maximize clicks vs Maximize conversions vs Target CPA vs Target ROAS at a glance

What data each strategy needs

The honest question to ask before picking a strategy is not "which is best" but "what can this campaign actually see". Three things decide it.

1. Conversion tracking that records the right action. If the tag fires on a thank-you page that people can reach without submitting the form, or counts every page view as a lead, Smart Bidding will optimise toward that error at full speed. Audit the conversion actions before changing the bidding, not after.
2. Enough conversions per campaign. Google does not set one universal minimum, but its help pages are clear that the time to calibrate depends on the number of conversions a campaign gets and on the length of the conversion cycle. A campaign that records a handful of conversions a month gives the system very little to learn from, and every result moves the bids a lot.
3. A conversion delay you understand. If most leads convert three days after the click, the last few days of data always look worse than they will end up. Judging a Target CPA campaign on yesterday's numbers punishes it for conversions that have not been recorded yet.

For value-based strategies add a fourth requirement: values that reflect real business outcomes. An ecommerce store can pass the order value. A lead-generation business has to assign values deliberately, for example a higher value for a quote request than a newsletter sign-up, or import offline values once a lead turns into revenue.

When to switch from one bidding strategy to another

Most accounts move along a path rather than jumping straight to the end. A sensible sequence for a new Search campaign looks like this:

1. Start with Manual CPC or Maximize clicks with a bid limit while the campaign collects its first clicks and you confirm the conversion tag fires correctly.
2. Move to Maximize conversions once conversions are recorded regularly and the numbers match what the sales team or the order system sees.
3. Add a Target CPA once the actual CPA under Maximize conversions has been stable for a few weeks. Set the target close to what the campaign is already achieving, not to the number you wish it achieved.
4. Move to Maximize conversion value or Target ROAS when conversions carry meaningful, differentiated values and revenue rather than lead count is the real goal.

Signs that it is time to move up a step: conversions arrive every week without gaps, the tracked count agrees with the CRM, and manual bid changes are taking more time than they return. Signs that it is time to step back: tracking broke or changed, the business changed what it counts as a conversion, or conversion volume dropped so far that the automated strategy is making large swings on very little data.

If you want to compare two strategies rather than guess, Google Ads experiments let you split a campaign's traffic between the current strategy and a trial strategy and compare results over the same dates. That is a cleaner test than switching and comparing this month against last month, which mixes the strategy change with seasonality and competitor moves.

How the learning period works

When a Smart Bidding strategy enters learning, the status column shows "Learning" next to the strategy. Google lists four triggers: a new or reactivated strategy, a change to the strategy's settings (such as the target), a composition change (campaigns, ad groups or keywords added or removed), and, on Shopping campaigns, some ad group target changes. Google's help text says calibration can take a few conversion cycles, typically one to two, and can be faster when there is more conversion data. Manual CPC has no learning period at all.

Three practical rules follow from that.

• Batch your changes. Moving a target every two days restarts the clock each time. Decide the change, make it once, and wait at least one full conversion cycle before reading the result.
• Change targets in moderate steps. A large cut to a Target CPA asks the system to find a very different set of auctions at once. Smaller steps let volume adjust gradually.
• Do not read the learning window as the verdict. Performance during learning is noisy. Google also notes the algorithm keeps learning after the label disappears, so "Learning" ending is not the same as the strategy being finished.

For short, predictable spikes such as a three-day sale, Smart Bidding offers seasonality adjustments, which tell the system to expect a change in conversion rate for a set date range. For tracking outages, data exclusions tell it to ignore conversion data from the affected dates. Both live in the advanced controls for bid strategies and are better options than changing targets around an event.

A hypothetical example

Imagine a clinic running a Search campaign on Maximize conversions. Over six weeks, its actual cost per booking settles around 600 baht, and bookings arrive every day. The team adds a Target CPA of 600 baht, matching what the campaign already achieves. The strategy enters learning, the team leaves it alone for two weeks, and only then considers lowering the target to 550 baht. Had they set 350 baht on day one because that is the figure they wanted, the campaign would likely have lost volume sharply while the system searched for auctions that could deliver it. The numbers here are invented to show the method, not a benchmark.

The August 2026 change to target-based bidding

On 17 August 2026 Google changed how Target CPA and Target ROAS behave on campaigns that are limited by budget, and the global rollout was completed on 27 August 2026. Before the change, a campaign with an aggressive target and a small budget could beat its target on paper because the budget held spend down. Now bidding works to deliver closer to the target the advertiser entered, even when the campaign is budget-limited. Google does not adjust targets or budgets automatically.

The practical effect is simple. If a campaign has been beating its Target CPA only because its budget kept it small, its CPA can rise toward the number you actually wrote down. Review every budget-limited campaign on a target-based strategy and set the target to the CPA or ROAS you genuinely want at full spend.

What this means for advertisers in Thailand

Three features of the Thai market affect bidding choices. First, many local businesses close sales in LINE or by phone rather than on the website. If the only tracked conversion is a form submission, Smart Bidding will undervalue the campaigns that drive LINE chats and calls. Track LINE add-friend clicks and call clicks as conversions, and where possible import the leads that became customers, so the system sees the full picture.

Second, many Thai SME accounts run several small campaigns, each with few conversions. Splitting conversions thinly across campaigns slows learning. Consolidating similar campaigns, or using a portfolio bid strategy shared across them, gives one strategy more data to work with.

Third, Thai retail calendars are full of short, sharp events: double-date sales such as 11.11 and 12.12, payday weekends and long holidays such as Songkran. Seasonality adjustments are built for exactly these windows, and they avoid the learning reset that comes with changing targets before and after each event.

Tracking quality sits underneath all of this. A clean GA4 and Google Ads conversion setup is the precondition for any automated strategy, which is why bidding reviews often start with a GA4 setup and migration review. Retailers bidding on product feeds face the same choices inside Google Shopping campaigns, where Target ROAS is the usual end point.

Frequently Asked Questions

Which Google Ads bidding strategy is best for a new campaign?

For a new campaign with no conversion history, Manual CPC or Maximize clicks with a maximum CPC bid limit is usually the safer start. Once conversion tracking is verified and conversions arrive regularly, move to Maximize conversions, then add a target.

Is Enhanced CPC still available?

No, Enhanced CPC has not been available for Search and Display campaigns since the week of 31 March 2025. Campaigns that had not been migrated now run on Manual CPC.

How long does the Smart Bidding learning period last?

Google says calibration typically takes one to two conversion cycles, and can be faster with more conversion data. The status is triggered by new strategies, setting changes, and campaigns, ad groups or keywords being added or removed.

Should I use Target CPA or Target ROAS?

Use Target CPA when every conversion is worth roughly the same to the business, and Target ROAS when conversion values differ meaningfully, such as ecommerce orders of different sizes. Target ROAS needs conversion goals that report two or more unique values, from real revenue or proxy values such as a lead score.

Why did my CPA rise after August 2026?

If the campaign is budget-limited and uses Target CPA or Target ROAS, the 17 August 2026 change makes bidding deliver closer to the target you entered. A target that was set lower than the campaign could reach at full spend now pulls CPA toward that target, so review and reset it.

Getting the strategy and the data right

Bidding strategy is the last decision, not the first: tracking, conversion values and campaign structure decide whether any automated strategy can work. If you want a second view on which Google Ads bidding strategies fit your account, or help rebuilding the conversion setup that feeds them, the Google Ads management team at Relevant Audience can review the account with you. Businesses that want search campaigns run as an ongoing service can also look at Relevant Search for Google Ads.