Google Ads Target Bidding Update: Why Budget-Limited Campaigns Face Rising Costs

Insights Paid Search

Launch Online

Performance Marketing Specialists

Read time4 mins

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By Elliot Smith, Account Director, Launch

Your Google Ads account is facing an algorithmic shift on August 17. For years, marketing teams have relied on an unearned efficiency discount. You set a £20 Target CPA on a campaign capped by daily spend, knowing Google’s algorithm would naturally chase the cheapest conversions first as it tries to conserve spend. The campaign delivered at £12, and efficiency metrics looked strong.  

That system behaviour ends on August 17th. Google is updating Smart Bidding across Search, Shopping, Performance Max, and Demand Gen. Going forward, budget-limited campaigns will bid strictly toward your set CPA or ROAS target rather than hunting for cheap edge-case conversions.  

I’m Elliot Smith, Account Director at Launch. I lead account teams driving performance across paid media platforms. Here is what is changing across the platform, why Google is making this update, and how marketing leaders can protect their acquisition margins before the deadline.  

TLDR: GOOGLE ADS TARGET BIDDING UPDATE

Beginning August 17th, Google Smart Bidding will treat Target CPA and Target ROAS on “Limited by budget” campaigns as literal targets. The algorithm will no longer bid conservatively to deliver conversions below your target. If your campaign target sits at £20 CPA, Google will adjust bids to deliver a £20 CPA, even if actual historical performance was £12. To prevent acquisition costs rising and conversion volume dropping, performance teams must audit budget-capped campaigns, adjust targets using Google’s Bid Target Adjustment tool, or test Maximize Conversions strategies through isolated experiments.  

Google ads bidding AI generated

Why Google Is Changing Smart Bidding  

Google states this update is designed to improve performance stability and predictability. Historically, budget-limited campaigns running target-based bidding experienced severe performance volatility when daily budgets were changed, particularly when budgets scaled up. When extra spend was added, CPAs or ROAS frequently spiked before settling.  

To eliminate this volatility, Google is updating its backend bidding algorithms. The system will now find conversions consistently at your entered target rather than holding back bids to stay well inside it.  

The Real Commercial Risk to Your Account 

If your Target CPA is set to £20 and your campaign status reads “Limited by budget”, Google will bid more aggressively to hit £20.  

If your teams take no action before August 17th, customer acquisition costs will rise overnight. This will not happen because creative fatigued or market demand dropped. It happens because the algorithm has been given explicit permission to bid up to your target.  

For brands operating on fixed monthly budgets, higher acquisition costs mean lower order volume. When each conversion costs more, your fixed daily spend buys fewer conversions, reducing overall conversion volume and/or revenue. 

Furthermore, as advertisers across your sector allow Smart Bidding to bid higher in budget-constrained auctions, cost-per-click (CPC) inflation across competitive auctions is a likely secondary effect.  

Your Three-Step Pre-Deadline Audit  

To protect account efficiency and maintain revenue volume, performance teams should execute this audit immediately: 

  • Filter for active campaigns with a “Limited by budget” status running Target CPA or Target ROAS.  
  • Compare your actual historical CPA or ROAS over a 30 to 60 day window against the target entered in system settings.  
  • Lower your Target CPA (or raise your Target ROAS) to match actual historical performance using Google’s Bid Target Adjustment tool.  

Strategic Alternatives: Experiments and Campaign Restructuring  

Lowering bid targets is the immediate fix, but two broader strategic moves should be evaluated: 

  • Test Maximise Conversions strategies: Bidding strategies like Maximize Conversions and Maximize Conversion Value are engineered specifically for budget-capped campaigns. If maintaining order volume on a fixed budget is your primary goal, test a Maximize strategy. De-risk the change by setting up a 50/50 experiment for 14 days rather than switching live campaigns directly. Just be mindful of increasing CPCs, because if demand is low on maximise strategies, Google will inflate CPC to spend the budget which in turn could lead to less traffic for your money and less conversions. 
  • Reorganise campaign structures: Review whether specific keywords or product groups are spending a disproportionate amount of the campaign budget. Splitting high spending generic keywords away from high-intent specific terms can remove the “Limited by budget” constraint entirely, allowing target bidding to operate without algorithmic caps.  

Reclaim Your Performance Control 

Automated bidding systems require constant human guidance. As ad platforms tighten target precision, unmonitored campaign settings present an immediate margin risk. Audit your budget-capped campaigns today, align bid targets with real performance, and test alternative bidding models through controlled experiments.   

CONTACT US

If your team needs an independent audit of your Google Ads account architecture ahead of these platform changes, contact our performance marketing specialists today

About the author

With 12 years of marketing experience, Elliot began his career in travel marketing. At Launch, he leads account teams to drive performance across paid media platforms, ensuring strategic direction and client success. 

Connect with Elliot on LinkedIn.