Google is preparing a fairly important change to Smart Bidding, and advertisers running campaigns with tight budgets may notice the difference first.
Starting August 17, Google Ads will change how Target CPA and Target ROAS bidding behave when a campaign is limited by budget. Instead of allowing budget constraints to indirectly push campaign efficiency beyond the advertiser’s stated target, Google says its bidding systems will put more weight on the target that was actually entered.
That sounds like a small technical adjustment. For some accounts, it probably will be. For campaigns that have spent months comfortably beating their CPA or ROAS targets while running into budget limits, though, performance could look different once the update takes effect.
Google Wants Smart Bidding Targets to Mean What They Say
The idea behind the Google Smart Bidding update is relatively straightforward.
If an advertiser sets a Target CPA or Target ROAS, Google wants its system to optimize around that number even when the campaign cannot spend more because of its daily budget.
Until now, some budget-limited campaigns could consistently perform better than the target. A campaign with a Target CPA of $50, for example, might regularly generate conversions at a considerably lower actual CPA because it simply did not have enough budget available to pursue additional conversions.
Under the new behavior, Google’s bidding system may become more willing to move performance toward the stated $50 target instead of continuing to preserve the unusually strong efficiency created by the budget restriction.
That distinction matters. A target that advertisers once treated as something closer to a ceiling could become a much more active instruction to the bidding system.
Budget Changes Should Become Less Disruptive
Google is also positioning the change as a way to reduce the performance swings that sometimes happen when advertisers adjust budgets.
Increasing a campaign budget can currently give Smart Bidding room to chase additional conversions, which may cause CPA to rise or ROAS to fall as the system moves closer to the campaign target. Cutting the budget can produce another adjustment.
The result is a slightly awkward situation where changing the amount of money available can also change the efficiency the system has been delivering.
Google says keeping the bidding target as the dominant efficiency signal should make those transitions more predictable.
In practical terms, an advertiser should be able to change a budget without creating quite as much confusion about whether the bidding system is suddenly working toward a different level of efficiency.
Some Advertisers May See Performance Get Worse — At Least on Paper
There is an uncomfortable part of this update.
Campaigns currently outperforming their targets may stop doing so.
Imagine a campaign targeting a 400% ROAS but routinely producing 550% because its budget is restricted. Once the change rolls out, Smart Bidding may have more freedom to pursue additional traffic while moving closer to the 400% target.
The campaign could generate additional conversion volume while showing a lower ROAS.
Technically, the bidding system would still be doing exactly what the advertiser requested. Someone reviewing the account without understanding the change, however, could easily look at the declining ROAS and assume performance has deteriorated.
That is why the gap between target performance and actual performance deserves attention before August 17.
Campaigns Without Budget Constraints Should See Little Change
Not every Google Ads campaign needs to be reconsidered.
Google says campaigns that are not limited by budget should largely continue operating as they do today. Target CPA and Target ROAS already function as the main controls over efficiency in those campaigns.
The biggest implications are therefore concentrated around campaigns where available budget has been restricting what Smart Bidding can do.
For advertisers managing large accounts, that narrows the audit considerably. There is little reason to start adjusting targets across every campaign simply because Google announced a bidding update.
The more useful place to look is the combination of budget limitation and unusually strong performance compared with the campaign target.
Old Target CPA and ROAS Settings May Suddenly Matter More
One potentially messy outcome is that some advertisers could discover they have been relying on outdated bidding targets without realizing it.
A Target CPA may have been entered months ago and left untouched because the campaign was consistently beating it. The same thing can happen with Target ROAS.
If budget limitations were helping produce that stronger performance, the old target may now start influencing the campaign more directly.
That makes this update less about finding a new bidding trick and more about checking whether the numbers already sitting inside Google Ads still make sense.
A business that genuinely needs a $35 CPA probably should not leave a $55 Target CPA in place simply because the campaign historically delivered conversions for $35 anyway.
The system may soon take that $55 instruction more literally.
Google Is Adding Tools to Flag Campaigns That Need Attention
Google is not leaving advertisers completely on their own before the rollout.
The company has introduced account notifications along with a review tool designed to identify campaigns that may require target adjustments.
Those warnings could be particularly useful for accounts with dozens or hundreds of campaigns, where manually comparing actual CPA or ROAS against every bidding target would quickly become tedious.
Still, automated recommendations deserve the same scrutiny as any other Google Ads recommendation. A target should reflect the economics of the business rather than simply the number Google suggests will generate more spending or conversion volume.
What Advertisers Should Check Before August 17
The simplest preparation is to find campaigns that are both budget-limited and substantially outperforming their Target CPA or Target ROAS.
Those are the campaigns most likely to expose the effects of the Google Smart Bidding update.
Look at whether the existing target still represents the result the business actually wants. If actual CPA is dramatically below Target CPA, ask whether you would genuinely be comfortable paying closer to the target amount for additional conversions.
For ROAS campaigns, the question is similar. If the campaign regularly returns 600% against a 400% Target ROAS, would the business still consider 400% acceptable if Google begins pursuing more volume?
If the answer is no, the bidding target probably deserves another look.
The Bigger Change Is How Advertisers Think About Budgets
Google’s update subtly separates two controls that advertisers sometimes allow to blur together.
The budget determines how much a campaign can spend.
The bidding target determines the efficiency the campaign should pursue.
Google wants those jobs to stay separate.
After August 17, advertisers may find it harder to use a restrictive budget as an accidental way of forcing Smart Bidding to outperform a looser CPA or ROAS target. If a particular efficiency level matters to the business, that expectation needs to be reflected in the target itself.
For experienced Google Ads managers, that may sound obvious. Real-world accounts are rarely that tidy.
Targets get inherited. Budgets get changed. Campaign objectives evolve. Numbers that made sense six months ago remain untouched because performance looks good enough.
This update could expose some of those forgotten settings rather quickly.
What Happens Next
The Google Smart Bidding update is scheduled to begin on August 17, 2026.
It is not a complete reinvention of automated bidding, and advertisers with unconstrained campaigns may barely notice it. Budget-limited campaigns are another story.
The important number may no longer be the CPA or ROAS a campaign happens to be producing today. It will be the target sitting inside the campaign telling Google what level of efficiency is acceptable.
Advertisers who have been comfortably outperforming loose targets should check those settings before the rollout rather than discovering the difference in a performance report afterward.
Sources
Search Engine Land — “Google explains what advertisers should expect from Smart Bidding changes”