Stop Wasting Ad Budget: Negative Keywords Explained
20 to 40 percent of ad spend in most local service accounts goes on clicks that were never going to convert. Negative keywords are the fix, and a single 20-minute weekly session with your Search Terms report is enough to recover 10 to 15 percent of that wasted spend within the first month, with no other changes to your account.
If you have ever looked at your Google Ads dashboard and thought "why is this costing me so much when the phone barely rings", the answer is often hiding in a report you have probably never opened: the Search Terms report. This is where negative keywords come in, and getting them right is one of the fastest, cheapest ways to stop money going to clicks that were never going to become a customer.
What Negative Keywords Are, in Plain English
A normal keyword tells Google "show my ad when someone searches this". A negative keyword does the opposite: it tells Google "never show my ad for this search". If you are a plumber and you add "jobs" as a negative keyword, someone searching "plumber jobs Manchester" will not trigger your ad and you will not pay for that click.
Without negatives, Google will match your ads to a much wider range of searches than you would choose yourself, especially if you are using broad match keywords, which is now Google's default recommendation. That flexibility brings in more volume, but a significant chunk of that volume is junk you are paying for.
On a £1,500 a month account, 20 to 40 percent wasted spend means £300 to £600 disappearing every single month before you even get to the question of whether your landing page or follow-up is any good.
MapLeads MediaWhere to Find Your Wasted Clicks
Inside Google Ads, go to Campaigns, then Insights and Reports, then Search Terms. This shows you the actual words and phrases people typed before your ad appeared and they clicked. This is the only reliable source of truth. Everything else is a guess.
The Negative Keyword Categories Every Local Business Should Block
Job seekers searching your trade name will never become customers. Block the whole category.
These people are solving it themselves, not booking you. High click rate, near-zero conversion rate.
Only block these if you do not genuinely compete on price. If you offer a free quote or consultation, use phrase match carefully to avoid blocking that too.
Add every town and city outside your realistic service radius. Google's location targeting is not perfect, especially on mobile, and people searching from elsewhere do trigger your ads.
Then layer on trade-specific exclusions. A private dentist might block "NHS". A makeup artist might block "course" or "kit". A roofer might block "insurance claim advice". You will not think of all of these upfront, which is why the weekly check matters more than the initial list.
Match Types: the Part That Trips People Up
Negative keywords have three match types. Picking the wrong one can accidentally block searches you actually want.
| Match type | What it blocks | Risk level | Best used for |
|---|---|---|---|
| Broad match | Any search containing all your words, in any order | High | Words you never want in any context, like "DIY" or "vacancy" |
| Phrase match | Searches containing that exact phrase, with extra words around it | Medium | Most cases, good middle ground and safe for words with double meanings |
| Exact match | Only that precise search term, nothing else | Low | Specific searches you want to block while keeping close variations live |
Rule of thumb: use exact or phrase match for anything with a legitimate double meaning, like "free" (you may still want to show for "free quote"), and reserve broad match negatives for words you never, ever want associated with your business.
A Realistic Weekly Routine That Takes 20 Minutes
- 01Open the Search Terms report once a week, same day each weekConsistency matters more than frequency. Pick a day and make it a habit. Monday morning before you check anything else works well for most people.
- 02Sort by cost, scan the top 20 to 30 rowsYou do not need to read every row. The expensive irrelevant searches are at the top. Anything below your cost-per-lead threshold with conversions is probably fine.
- 03Add anything irrelevant at phrase match as the defaultUnless it clearly never belongs in any context (use broad) or you need to be very surgical about one specific variation (use exact). Phrase match covers most situations safely.
- 04Flag any zero-conversion searches above your cost-per-lead ceilingThese are the silent budget killers. A search that has cost you £80 with zero enquiries is not an outlier, it is a pattern waiting to be caught.
If you are running Performance Max campaigns, Google only expanded proper negative keyword support through 2025. Previously it was capped at 100 exclusions per campaign, which made it almost impossible to control wasted spend there. If your account still has PMax running with an old, thin negative list, that is worth revisiting now that the limits have loosened.
What Negative Keywords Will Not Fix
Being honest: negative keywords stop obviously irrelevant searches, but they will not fix a landing page that does not explain your offer clearly, a form that is too long, or a keyword you chose to bid on that attracts low-intent traffic by design. They are a defensive tool, not a growth strategy.
Think of them as plugging leaks in a bucket. Useful and necessary, but you still need the bucket to be the right shape. Once the wasted spend is plugged, the next question is whether the relevant traffic you are keeping is actually being converted by what it lands on.
If nobody has touched your negative keyword list in the last three months, you are very likely leaking budget right now. A single weekly session with the Search Terms report, done consistently, is one of the highest-return activities in the whole account, often recovering 10 to 15 percent of wasted spend within a month with no other changes at all.
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