Negative Keywords: The Fastest Way to Cut Wasted Google Ads Spend
Negative keywords stop your ads showing for searches you don’t want to pay for. The common advice stops there, with a generic list of words to exclude. It also misses the part that actually determines whether negatives save you money: an audit of 31 Google Ads accounts covering $133 million in spend found the size of a negative keyword list has close to no relationship with how much budget gets wasted (a correlation near zero). A 2,000-line negative list can still leak spend, and a lean, well-structured one can plug most of it. The difference is where the negatives sit and what they’re built to catch, not how many there are.
This matters more in 2026 than it did a few years ago. AI Max for Search and broad match are now built to expand deliberately into queries that are thematically related to your keywords, not just close variants, with negative keywords as one of the main controls for keeping that expansion on-topic. That’s a genuine win for reach, but it shifts more of the burden of staying relevant onto your negative keyword structure. A list built for 2022’s match type behaviour is not built for 2026’s.
Why “just add more negatives” doesn’t work
Most guides treat negative keywords as a reactive list: check the search terms report, spot a bad query, add it as an exact or phrase negative, repeat. That catches individual leaks, but it doesn’t catch the category they came from. If “free quote template” shows up this week, “free pricing guide” will show up next week, and a single-term approach means you’re always one search behind the next wasted click.
The structural fix is to think in exclusion categories rather than individual terms. Most Australian small business accounts waste spend on some combination of:
- Research and DIY intent (“how to”, “diy”, “template”, “tutorial”, “guide” when you sell a done-for-you service)
- Free or lowest-price seekers (“free”, “cheap”, “cheapest”, “no cost”)
- Wrong audience (“jobs”, “careers”, “salary”, “course”, “training” when these aren’t your offer)
- Wrong location (suburbs or cities outside your service area, especially on broad match)
- Wrong product or service line (a term that’s adjacent to what you sell but not actually it, for example “lawn mowing” on a landscape design account)
- Structural overlap between your own ad groups, where two tightly themed ad groups both match the same broad query and start competing with each other instead of with outside advertisers
Building a negative list against these categories, rather than one term at a time, is what actually moves the needle. A single well-chosen phrase negative like “free quote” can block dozens of future variants that a list of exact-match single words never would.
Where to put each type of negative
Google Ads lets you add negative keywords at three levels, and using the wrong one is a quiet source of either wasted spend or (worse) suppressed impressions on keywords you want.
| Level | Best for | Risk if misused |
|---|---|---|
| Account-level (shared list) | Universal non-buyer terms that apply to every campaign (free, DIY, jobs, careers) | Can silently block a legitimate campaign if applied too broadly |
| Campaign-level | Exclusions specific to one campaign’s geography, product line or intent | Easy to forget to replicate across new campaigns |
| Ad group-level | Keeping tightly themed ad groups from cannibalising each other inside one campaign | Narrow scope; won’t catch issues that span campaigns |
Shared negative keyword lists (built once, attached to multiple campaigns) are worth setting up early if you run more than two or three campaigns. They keep your universal exclusions in one place instead of duplicated and drifting out of sync across campaigns, which is one of the most common ways negative lists quietly stop working as an account grows.
The conflict most accounts never check
A negative keyword conflict happens when a negative you’ve added overlaps with a keyword you’re actively bidding on, and it silently suppresses impressions on that keyword with no error message. This is most common when a broad account-level negative (“services” as a broad match negative, for example) accidentally blocks a legitimate keyword variant.
If a keyword’s impressions unexpectedly drop to near zero with no change in budget or bid, check it against your negative lists before assuming it’s a competition or Quality Score issue. Google Ads’ Keyword Diagnosis tool (under the keyword’s status column) flags this directly and will tell you exactly which negative is blocking it.
A worked example: a typical trades account
Here’s how the category approach plays out in practice. Picture a Sydney plumbing business running broad match Search campaigns with a thin negative list, mostly single words added reactively whenever something stood out. A few months of search term data for an account like this typically surfaces four recurring leak categories: DIY plumbing searches (“how to fix a leaking tap”), jobs and apprenticeship searches (“plumber apprenticeship sydney”), searches for suburbs well outside the service radius, and emergency-adjacent but unrelated trades (“emergency electrician”, “emergency locksmith”).
Rather than excluding each query individually as it appears, the fix is to build four phrase and broad match negative categories at the account level (“how to”, “apprenticeship”, “jobs”, plus the specific out-of-area suburb list) and add campaign-level geography negatives matched to the actual service radius. That single structural pass, not an ever-expanding word list, is what pre-emptively blocks entire categories of future variants instead of chasing them one query at a time.
A simple audit framework you can run this week
- Pull the search terms report for the last 30 to 90 days (Campaigns > Insights and reports > Search terms, or Keywords > Search terms). Sort by cost, not clicks, so the worst offenders surface first.
- Group, don’t list. As you scan, write down categories, not individual terms: “DIY intent”, “wrong suburb”, “job seekers”, “adjacent but wrong service”. Most accounts find three to six recurring categories.
- Decide the level for each category. Universal and account-wide -> shared negative list. Specific to one campaign’s geography or product -> campaign-level. Specific to ad group overlap -> ad group-level.
- Add phrase or broad match negatives for categories, exact match only for genuinely one-off terms. A phrase negative catches future variants; an exact match negative only catches that exact string.
- Check for conflicts before adding anything broad: search your existing keyword list for any overlap with the new negative.
- Re-run this monthly, more often for broad match and Performance Max campaigns, which are built to keep expanding into new query territory.
Negative keywords are a structure, not a chore
The habit of “check the report, add a word, move on” isn’t wrong, it’s just incomplete. The accounts that genuinely cut wasted spend treat negative keywords as part of campaign architecture: the right exclusion, at the right level, built around a category rather than a single query. That’s especially true now that broad match and AI Max are designed to expand further than they used to; the structure around them has to do more work to keep that reach pointed at the right audience.
If your account’s search terms report hasn’t been properly audited in the last few months, that is one of the highest-leverage, lowest-cost fixes available before touching bids or budgets. It’s a standard part of how we run Google Ads management for clients, including a full Google Ads account audit that maps exactly where spend is leaking. If you want a second set of eyes on your own account, book a free strategy call. Once your negatives are structured properly, the next place to look is whether your conversion tracking is feeding Smart Bidding clean data to optimise against.
