Google Ads 'Limited by budget' changed in 2026: what to check now

If a Google Ads campaign is marked Limited by budget and uses Target CPA or Target ROAS, a significant bidding change is now live. Since 17 August 2026, Google has been optimising these budget-constrained campaigns more consistently towards the target you actually set. The global rollout finished on 27 August.

That sounds technical, but the practical consequence is simple: if your campaign had been beating its target by a wide margin, you should not assume it will keep doing so. A campaign with a £20 Target CPA that had been delivering £12 conversions may now move closer to £20 unless you change the target, budget or bidding approach.

Google has not automatically changed advertisers' budgets or targets. The number sitting in your account therefore matters more than it did before. Google's official guidance on the change is explicit about this.

What changed with Google Ads Limited by budget campaigns?

Before this update, some campaigns using target-based Smart Bidding could be limited by budget while still substantially outperforming the target entered in the account. Google says performance could also fluctuate when budgets changed.

The new behaviour is designed to make those campaigns deliver more consistently towards the stated bidding target, including when the budget changes.

Google's own example is useful. If a campaign has a Target CPA of £10 but has recently achieved an actual CPA of £5, it can now move closer to the £10 target. If the business genuinely needs to stay around £5, Google suggests changing the target to £5 or another figure that reflects the real commercial goal.

This is not a reason to panic or immediately halve every Target CPA. It is a reason to check whether the target in Google Ads still represents the economics of the business.

Which campaigns are affected?

The change applies to campaigns that are both limited by budget and using an affected target-based bid strategy.

That includes Target CPA and Target ROAS across Search, Shopping, Performance Max, Demand Gen and Travel campaigns. Target CPC is also affected for Demand Gen. Google says App campaigns, Video Reach campaigns and Video View campaigns continue to use the previous bidding behaviour.

If a Target CPA or Target ROAS campaign is not budget-constrained, Google says its behaviour is not changed by this update. That distinction matters: seeing Target ROAS in an account does not automatically mean there is a problem.

If you are still deciding which campaign type belongs in the account, our guide to choosing Meta or Google Ads first starts one level earlier: where the demand exists and which platform should get the budget in the first place.

Why this matters for a small business

Small businesses often run close to a hard daily budget. That makes the new behaviour particularly relevant.

Imagine an ecommerce campaign with a Target ROAS of 300%. In practice, it has been returning 500% while spending all the budget available. The old performance can make 500% feel like the campaign's natural level. But if the campaign is budget-constrained and the account still says 300%, the system now has more licence to scale towards the target you told it was acceptable.

The same logic works with leads. If a service business tells Google that £40 is an acceptable Target CPA but the campaign has historically generated leads for £25, £25 is not automatically protected just because that is what happened last month.

The target is a business instruction, not a decorative setting.

First check: is the campaign actually Limited by budget?

Do not make changes based on this article alone. Open Google Ads and identify the campaigns that actually show the Limited by budget status.

Google describes this status as a campaign whose average daily budget is lower than the recommended amount, so ads are not able to show as often as they otherwise could. A limited campaign can still be profitable; the label is not a verdict that the campaign is badly run.

The relevant combination is:

• the campaign is Limited by budget; and
• it uses Target CPA, Target ROAS, or Target CPC in the applicable Demand Gen case.

If neither condition applies, this specific August 2026 change is not the reason to alter the campaign.

Second check: compare the target with recent actual performance

Look at the target entered in the campaign and compare it with what the campaign has actually delivered over a sensible period.

For Target CPA, compare the target cost per acquisition with actual CPA. For Target ROAS, compare the target return with actual conversion value divided by cost.

The gap is the important part. A Target CPA of £30 with an actual CPA around £29 tells a very different story from a £30 target with an actual CPA around £15.

Do not choose the period because it makes the result look good. Account for promotions, stock-outs, unusual seasonal demand and tracking changes. If conversion tracking changed halfway through the period, fix the measurement question before drawing a bidding conclusion.

That is why checking tracking and commercial maths before spending on ads still comes before bidding optimisation.

Third check: decide what CPA or ROAS the business can actually afford

The best target is not necessarily last month's actual performance. It is the performance level at which the campaign still makes commercial sense.

For ecommerce, start with contribution margin rather than revenue alone. A 400% ROAS can be excellent for one product and unprofitable for another once product cost, fulfilment, discounts, returns and payment fees are included.

For lead generation, work backwards from the value of a customer and the proportion of leads that become paying customers. If one in five qualified leads converts and a new customer can profitably cost £250 to acquire, a £50 lead may be viable. If only one in ten converts, the same £50 lead implies £500 acquisition cost.

This is where a bidding target becomes useful: it translates the business economics into an instruction the platform can optimise towards.

Your four practical options

1. Keep the existing target

If the Target CPA or Target ROAS already reflects the real business goal, Google says no change is required. Just recognise that a campaign which previously overachieved that target may now move closer to it.

2. Move the target towards recent performance

If the campaign has been materially outperforming its stated target and you need to preserve that efficiency, adjust the target to a level that better reflects the result you actually need.

Google provides a Bid Target Adjustment Tool for affected advertisers. Its FAQ confirms the rollout completed globally on 27 August 2026 and recommends reviewing limited-by-budget campaigns that historically performed better than their targets.

3. Choose a custom target based on margin

Recent performance is evidence, not necessarily the answer. If a campaign has delivered a £20 CPA but the business can profitably acquire customers at £25, a £25 target may be a rational choice if the goal is additional volume.

Likewise, demanding an unrealistically high ROAS can choke volume. The right target balances efficiency with the amount of profitable demand available.

4. Change the bidding strategy

Google also points to Maximise conversions or Maximise conversion value without a target as alternatives. These strategies aim to use the available budget to maximise the selected outcome, so CPA or ROAS can fluctuate as budget changes.

This is not automatically better. Removing a target removes a constraint. Do it because that matches the business objective, not because a recommendation card suggests it.

Should you simply increase the budget?

Sometimes. If the campaign is profitable at the stated target and there is more worthwhile demand available, increasing budget can be the cleanest way to scale.

But “Limited by budget” is not an instruction to spend more money. Before increasing budget, check three things: the target is commercially sound, conversion tracking is trustworthy, and the landing page can handle more paid traffic.

Google's definition of Limited by budget makes clear that the status can occur simply because the daily budget is low relative to the available targeting and auction opportunities. More available traffic is not the same thing as more profitable traffic.

Do not make several big changes at once

A common response to performance movement is to change the target, increase the budget, rewrite ads and alter conversion actions in the same afternoon. That makes diagnosis harder.

Change the variable that has a clear business reason behind it, document the date, and give the campaign enough time and conversion volume to show what happened. Smart Bidding uses auction-time signals and predicted conversion likelihood, so short-term movement after a material change is not unusual. Google defines Smart Bidding as its AI-based auction-time optimisation for conversions or conversion value.

A 15-minute account check

1. Filter campaigns for Limited by budget.
2. Identify which of those use Target CPA or Target ROAS.
3. Write down the current target beside recent actual CPA or ROAS.
4. Check that conversion tracking and values are still correct.
5. Compare the target with the maximum CPA or minimum ROAS the business can genuinely tolerate.
6. Keep, tighten or reset the target deliberately.
7. Only increase budget if the economics justify buying more volume.

If the campaign itself needs rebuilding rather than another settings tweak, Mind the Shop's Single campaign set-up covers one Search, Shopping, Performance Max or Meta campaign with tracking checked before launch. For a build plus 30 days of optimisation, the Ads launch sprint is the broader option.

The useful takeaway

The August change does not make Target CPA or Target ROAS worse. It makes the target you entered more consequential when the campaign is budget-constrained.

If your account says a £40 CPA is acceptable, make sure £40 really is acceptable. If your campaign has been quietly delivering £22 and the business needs £22 to remain profitable, leaving £40 in the settings and hoping historical performance continues is no longer a sensible plan.

Start with the business maths, then make the bidding setting match it.