If your Google Ads cost-per-acquisition has crept up since mid-August and you haven't touched a single setting, you're not imagining it and your account isn't broken. Google changed how budget-limited Target CPA and Target ROAS campaigns deliver, and it landed quietly on 17 August 2026 with almost no fanfare outside the ads community.
Here's the short version: if your campaign was spending less than its daily budget while beating its target, Google used to let that ride. Now it pushes delivery closer to the number you actually typed in. Beating your target used to be a bonus. Now it's treated as a signal to spend more, not a result to protect.
If your Google Ads cost-per-acquisition has crept up since mid-August and you haven't touched a single setting, you're not imagining it and your account isn't broken. Google changed how budget-limited Target CPA and Target ROAS campaigns deliver, and it landed quietly on 17 August 2026 with almost no fanfare outside the ads community.
Here's the short version: if your campaign was spending less than its daily budget while beating its target, Google used to let that ride. Now it pushes delivery closer to the number you actually typed in. Beating your target used to be a bonus. Now it's treated as a signal to spend more, not a result to protect.
Key summary
- From 17 August 2026, Google Ads changed delivery behaviour for budget-limited Target CPA (tCPA) and Target ROAS (tROAS) campaigns
- Campaigns that were beating their target (e.g. an actual CPA of $5 against a $10 target) are now being pushed closer to the stated target
- It applies across Search, Shopping, Performance Max, Demand Gen, and Travel campaigns using target-based bidding
- Nothing needs to be "broken" in your account for this to affect you. It's a platform-wide delivery change, not an account issue
- Google shipped a Bid Target Adjustment Tool in early July 2026 that shows 12 months of history to help you reset targets sensibly
- Your reporting periods either side of 17 August need a mental asterisk, comparing before and after like-for-like will look like a performance drop that isn't one
What actually changed on 17 August 2026
Target CPA and Target ROAS have always worked as goals, not hard caps. Google's bidding system aims for the number you set, but it's never been perfectly precise. Some campaigns overperform, some underperform, and it generally balances out.
The change is specifically about budget-limited campaigns: ones that aren't spending their full daily budget because Google can't find enough auctions to fill it at your target. Previously, if that under-spending campaign happened to be smashing its CPA target, Google would let it keep smashing it. As of 17 August, Google's systems now treat that headroom as an opportunity to spend more and drift the CPA up toward your actual target figure.
In plain English: overperformance used to be free money. Now it gets absorbed back into "on target" delivery.
Why your CPA crept up even though you didn't touch anything
This is the bit that trips people up. You didn't raise your budget. You didn't loosen your target. You didn't add new keywords or change your bidding strategy. And yet the CPA graph in your account has been climbing since mid-August.
That's expected under the new behaviour. If your account was previously beating target because it was budget-constrained, Google now has more licence to spend that unused budget and bring your average CPA closer to what you asked for. Nobody has made a mistake here: Google is recalibrating what "hitting target" means for campaigns that had room to spend more.
The uncomfortable part is that a lot of advertisers had, without realising it, been quietly benefiting from Google being conservative. That conservatism is gone.
Which campaign types are affected
The change applies to any campaign on target-based bidding that's budget-limited, across:
- Search campaigns on Target CPA or Target ROAS
- Shopping campaigns on Target ROAS
- Performance Max campaigns using target-based goals
- Demand Gen campaigns on Target CPA
- Travel campaigns using target-based bidding
If your account runs entirely on Maximise Conversions or Maximise Conversion Value without a target set, this specific change doesn't apply to you directly, though it's still worth watching your numbers given how much Google's bidding systems evolve behind the scenes.
How to audit your targets before the numbers get away from you
Don't wait for a full reporting cycle to notice the drift. Do this now:
- Pull a 12-month view of actual CPA/ROAS versus target for every campaign on target-based bidding.
- Flag any campaign that was consistently beating target by more than 15–20%. Those are the ones most exposed to this change.
- Decide deliberately whether to tighten the target to protect margin, or accept the higher spend because the extra volume is worth it.
- Re-set targets to a number you're actually comfortable with, rather than one that was only ever hit because the campaign was under-spending.
This isn't a one-off fix. Treat it as a standing habit. Review target-based campaigns monthly, not just when something looks off.
Using Google's Bid Target Adjustment Tool
Google rolled out a Bid Target Adjustment Tool inside the platform from early July 2026, specifically to help advertisers get ahead of this change. It surfaces 12 months of historical performance against your current targets, so you can see exactly where you were overperforming before Google's systems start closing that gap for you.
If you haven't opened it yet, it's sitting in your account notifications or accessible through your campaign settings. It won't make the decision for you, but it removes the guesswork about which campaigns to prioritise first.
What this means for your reporting periods
If you're comparing performance before and after 17 August 2026 in a monthly or quarterly report, expect CPA to look worse even if nothing else about the account changed. It's a platform-level shift, and it's worth calling out explicitly in client reporting or your own internal numbers so nobody starts second-guessing a campaign that's actually performing exactly as it should.
Treat 17 August as a line in the sand. Benchmark from that date forward, not across it.
Frequently Asked Questions
Why did my Google Ads CPA go up if I didn't change anything?
Google changed how budget-limited Target CPA and Target ROAS campaigns deliver from 17 August 2026. Campaigns that were previously beating their target are now being pushed closer to the actual target figure, which shows up as a CPA increase with no account-side cause.
Does this affect Maximise Conversions campaigns?
No, this change specifically affects campaigns using target-based bidding (Target CPA or Target ROAS) that are budget-limited. Campaigns on Maximise Conversions or Maximise Conversion Value without a set target aren't directly affected by this particular change.
Should I lower my Target CPA to compensate?
Not automatically. Start by auditing how much headroom each campaign actually had before 17 August using the Bid Target Adjustment Tool, then make a deliberate call on each campaign rather than applying a blanket fix.
Is this the same as Google's tROAS enforcement everyone was talking about mid-year?
Yes. This is that change. It was flagged in Google's product notes and in-account notifications from around June and July 2026, and took effect on 17 August 2026.
Will this keep happening with future updates?
Almost certainly, in some form. Google's bidding systems are updated continuously. The practical takeaway isn't to panic about this specific change, but to build a habit of checking target-based campaigns against a rolling 12-month view rather than assuming "set and forget" still applies.
Wrapping up
Nothing is wrong with your Google Ads account. Google changed how it treats campaigns that were beating their targets, and that shows up as CPA creep even when you haven't touched a thing. The fix isn't complicated: audit your targets against real history using the Bid Target Adjustment Tool, decide deliberately what you're comfortable paying, and reset your reporting baseline from 17 August 2026 onward.
