At DeltaShore, we spend a lot of our time watching the platforms our clients’ budgets live on. This week, Google Ads is making a change worth knowing about before it lands.
From 17 August 2026, Google is updating how Smart Bidding behaves for campaigns using Target CPA or Target ROAS that are marked “Limited by budget.” If that’s you, here’s what’s actually changing, what isn’t, and what we’re doing about it for our own clients.
The Problem Google Is Fixing
Today, if a campaign is “Limited by budget” and using a target-based bid strategy, it can quietly
overperform its stated target — getting conversions cheaper (or more valuable) than the number you actually set. Sounds great, until you touch the budget — adjusting it has historically caused unpredictable swings, because the system readjusts back toward the stated target once more budget’s available.
Google’s fix: from 17 August, budget-limited campaigns will optimise more consistently toward the target you’ve set — regardless of budget — so scaling up or down should behave more predictably.
Say your Target CPA is £10, but your actual CPA has been running at £5 because the campaign’s been budget-constrained. After 17 August, that campaign will start optimising back toward £10 — unless you update the target first to reflect the £5 you’ve actually been achieving.
In short: if your set target doesn’t match your real performance, expect some volatility from the 18th.
- No automatic changes — Google won’t touch your budgets or bid targets for you
- No forced extra spend — your daily/monthly budget caps are still respected
- Unconstrained campaigns are unaffected
- Applies to Search, Shopping, PMax, Demand Gen and Travel. App/Video reach/Video view campaigns are unaffected; Hotel and Display already work this way
What We’re Doing About It
This week we’re going through every client account: flagging campaigns “Limited by budget” on Target CPA/ROAS, comparing set target vs. actual performance, and updating where there’s a meaningful gap — so nobody wakes up on the 18th to an unexplained dip.
Google’s also rolled out in-account notifications and a Bid Target Adjustment Tool (live since 6 July) — worth checking if you manage your own account.
Genuinely sensible change — unpredictable behaviour on budget-limited campaigns has been a long-running headache. But “Google won’t do it for you” is doing a lot of work in that sentence. If nobody checks your targets before the 17th, performance could shift without you ever knowing why.
Not sure if your account’s affected, or you’d rather someone else worry about it? Get in touch, we’re happy to take a look.
