Google says it is changing Target ROAS and Target CPA behavior for budget constrained campaigns to make performance more predictable and easier to scale. The current behavior can allow some campaigns to outperform their stated targets, then fluctuate when budgets change.
The change starts on August 17, 2026. Google wants affected campaigns to optimize more consistently toward the target the advertiser has actually entered.
For advertisers, the consequence is simple: the target needs to represent a real business objective. A loose target that has been sitting in the account for months may become more influential.
What problem is Google trying to solve?
Google says some campaigns marked as limited by budget can overperform their stated Target CPA or Target ROAS. That may sound entirely positive, but it can make the bidding target less predictable as a control.
For example, a campaign could have a Target CPA of $100 while actually acquiring conversions for $60. If the advertiser assumes $60 is normal and then increases the budget, the campaign may not scale at exactly the same efficiency.
In Google's FAQ about the change, Google says the existing behavior can be confusing and create unpredictable results when budgets are adjusted.
The stated goal is more reliable control and more predictable scaling.
Why does being limited by budget matter?
A limited by budget campaign does not have enough budget to capture all of the traffic the bidding system believes is available under the current settings. That constraint changes how the system can pursue volume.
If a campaign is achieving much better efficiency than its target while budget constrained, increasing budget can expose the campaign to additional auctions. Those extra opportunities may be less efficient than the small set the campaign was previously able to buy.
Google's new behavior is intended to make the stated target a more consistent reference point whether the budget is tight or increased.
This is why the August update is focused on budget constrained campaigns rather than every campaign using Smart Bidding.
Why would Google want campaigns to perform closer to their targets?
A target based strategy is supposed to express an advertiser's desired efficiency. If an advertiser enters a 400% Target ROAS, the system should be able to treat that number as a meaningful objective when seeking additional conversion value.
If campaigns routinely perform far above the target only because the budget is restrictive, the advertiser may misunderstand what will happen when more budget becomes available.
By aligning performance more consistently with the target, Google can make the relationship between target, budget and scale easier to forecast.
That does not mean Google guarantees an exact CPA or ROAS. Actual results can still vary because of auction competition, demand, conversion behavior and other factors.
Does this change mainly benefit Google or advertisers?
Google's stated rationale is advertiser control and predictability. More consistent target based bidding should make it easier to understand what efficiency level the system will pursue as budgets change.
There can also be a commercial consequence for Google. If an advertiser sets a relatively loose target and then allows a larger budget, the system may be able to enter more auctions and capture more conversion volume while staying around the stated objective.
That second point is an inference about the economics of the system, not Google's stated reason for the update. Advertisers should therefore focus on the part they control: setting a target that reflects their acceptable economics.
If 300% ROAS is genuinely profitable, a campaign moving from 500% toward 300% may still be commercially successful if the additional volume creates more total profit. If 300% would be unprofitable, the target is too loose for the business.
Why can better ROAS still produce a worse business decision?
Higher ROAS is usually attractive, but maximizing ROAS at all costs can restrict scale. A company may prefer a lower but still profitable ROAS if that produces materially more revenue or qualified pipeline.
For example, a campaign producing 700% ROAS on a very small budget may generate less total profit than a campaign producing 450% ROAS at three times the conversion volume. The correct target depends on margin, sales capacity and growth priorities.
For B2B advertisers, platform ROAS can also be incomplete if conversion value is based on lead forms instead of closed revenue. In that case, qualified pipeline and customer acquisition economics deserve more weight.
This is why Target ROAS should be connected with your wider marketing budget allocation instead of treated as an isolated Google Ads number.
What should advertisers do with Google's explanation?
Treat the update as a reason to audit targets, not as a reason to panic. Check whether campaigns are limited by budget, whether actual performance is materially better than the target, and whether the target still reflects your business objective.
If the target is accurate, Google says no change is required. If recent performance is better than the target and you want to preserve that efficiency, Google provides the Bid Target Adjustment Tool to help update it.
After changes, evaluate performance over one to two conversion cycles rather than reacting to short term noise. This is especially important for longer B2B sales and conversion paths.