If a retail campaign says “Limited by budget”, the first number to inspect is now the bid target. On 17 August 2026, Google began a gradual global rollout that changes how target-based bidding behaves when a campaign is budget-constrained.

This did not alter the warning itself. It changed the relationship between budget and efficiency. A Target ROAS that once looked harmless because the campaign consistently beat it can now have more influence over the result.

What changed on 17 August

Google says affected campaigns will optimise more consistently toward their Target CPA or Target ROAS, even when they are limited by budget or the budget changes. Under the previous behaviour, some constrained campaigns performed better than the target entered in the account.

Take a campaign with a 300% Target ROAS that has recently delivered 450%. After the change, that campaign may move closer to the entered 300% target if nothing else changes. That is the Target ROAS version of Google’s own Target CPA example. It is an explanation of the mechanism, not a forecast that every campaign will land exactly on its target.

The rollout covers budget-constrained Search, Shopping, Performance Max, Demand Gen and Travel campaigns using Target CPA or Target ROAS. Target CPC is included for Demand Gen. Campaigns using those strategies without a budget constraint are outside this change. Manual CPC and Target Impression Share are also outside it.

Google has not automatically raised budgets, edited bid targets or changed the auction. The rollout is gradual, so accounts may not all show the new behaviour at the same time.

The warning still says nothing about profit

“Limited by budget” means the current budget cannot capture all available traffic under the campaign’s bids, targets and targeting. It does not tell you whether the next euro of traffic will leave any contribution.

That distinction matters for a large catalogue. One blended Target ROAS can cover products with very different margins, return rates and fulfilment costs. Raising the campaign budget may buy more sales at the stated target while sending more spend to a product mix the business would not choose deliberately.

The warning is evidence of capacity. The commercial decision still belongs to the retailer.

Rebuild the target from the product economics

Put three figures beside every affected campaign: the entered target, recent actual performance and the efficiency the business requires.

The third figure needs finance and merchandising inputs. Start with gross margin, then account for discounts, fulfilment, returns, payment or marketplace fees and the contribution expected after advertising. Recent platform ROAS shows what delivery achieved. It does not define what the business can afford.

If one campaign contains ranges with materially different economics, a single target may still hide the decision. If those ranges require different Target ROAS thresholds, separate them into campaigns with different targets. Use listing groups or custom labels to control product inclusion and reporting within a campaign. The broader guide to Performance Max controls explains why margin-based structure matters.

Google’s tool does the edit, not the judgement

The Bid Target Adjustment Tool is available through Google’s “Review your campaign targets” notification and campaign bidding settings. It helps surface affected campaigns, compare recent performance with the entered target and apply an adjustment.

That is useful account hygiene, but “Apply” is a business choice. Matching recent performance can preserve an efficiency level that was real and stable. It can also preserve a promotion-heavy period, brand-led demand or an unprofitable product mix. Google does not provide a recommended target when a campaign has fewer than seven conversions because it says performance for those campaigns can be unpredictable.

For each campaign, choose deliberately:

  • Keep the target if it already represents the efficiency the business wants.
  • Enter a custom target if margin economics require a different result.
  • Align the target with stable recent performance if that performance is commercially sound.
  • Increase budget if the target is profitable and more volume is the goal.
  • Consider Maximize conversion value when the budget is fixed and variable efficiency is an acceptable trade.

For portfolio bidding and shared budgets, target actions must be taken at the portfolio or shared-budget level. In a portfolio with non-shared budgets, only constrained campaigns are affected; in a constrained shared budget, Google says the impact is distributed uniformly across the campaigns in that group.

Give the rollout time to become measurable

For Performance Max, watch actual versus target ROAS, conversion value, spend and channel allocation. Google says multi-channel campaigns can redistribute traffic across channels under the new behaviour.

Avoid diagnosing the change from a few noisy days. Google recommends waiting one to two conversion cycles before judging performance in the bid strategy report. It also warns that bid and budget forecasts may be temporarily inaccurate from 17 to 31 August 2026.

The useful audit ends with a target the business is prepared to buy at. Once that number is credible, budget becomes a scaling decision instead of an answer to a warning in the interface.