If you’ve ever run Google Ads and wondered where the budget went, negative keywords are a large part of the answer. They’re the most under-used feature in paid search, and getting them wrong (or skipping them entirely) is one of the most reliable ways to burn through ad spend on people who were never going to buy anything.
The concept is simple: a negative keyword tells Google not to show your ad for searches containing that word or phrase. You’re not adding targets, you’re removing irrelevant ones. Done properly, negatives mean your budget only gets spent on searches that could plausibly turn into business.
Why this matters so much
Google’s broad and phrase match types will show your ad for searches that are tangentially related to your keywords at best, and completely irrelevant at worst. A plumber bidding on “plumber London” can easily end up showing for “plumber salary London”, “how to become a plumber London”, and “plumber apprenticeship London”. None of those people want to hire anyone right now. Google charged for those clicks anyway.
Negative keywords are what stop that.
Match types for negatives
Negative keywords use the same match type logic as positive ones.
Broad match negative (the default) blocks your ad when all the words in the negative appear in the search, in any order. Phrase match negative blocks searches containing that exact sequence of words. Exact match negative only blocks that one precise query, nothing else.
Phrase match negatives are the most useful starting point for most campaigns. Specific enough to be meaningful, broad enough to catch variations without over-blocking legitimate searches.
Building your initial list before launch
You don’t need search data to make a start. Predictable categories of irrelevant searches exist for almost every business:
Job and career terms: jobs, job, career, salary, apprenticeship, how to become, training course. Unless you’re recruiting, anyone searching these isn’t a customer.
Free-related terms: free, DIY, how to, template, example, tutorial. People looking to do it themselves rather than pay someone.
Research and study terms: what is, definition, meaning, history, statistics, case study. Informational searches with no commercial intent.
Competitor names: specific competitors, unless you’re deliberately running a comparison campaign.
Add these before the campaign goes live. You’ll save budget from day one instead of running a week of data collection and then retrospectively blocking the obvious ones.
Building from search term reports
Once a campaign is running, check the search terms report regularly. It shows the actual queries that triggered your ads, not just the keywords you’re bidding on. Google’s matching is broader than most people expect, and the report will surface things you’d never have predicted. Check it weekly for the first few months.
Any search that’s clearly irrelevant, isn’t converting, and has no plausible route to a sale gets added as a negative. Do this consistently and the campaign slowly becomes more focused. Stop doing it and quality drifts.
Negative keyword lists
Google Ads lets you create shared negative keyword lists that apply across multiple campaigns. If you’re running several campaigns for the same business, build a master exclusion list and apply it everywhere. Add a new negative once and it takes effect across all campaigns, rather than having to hunt through each one individually.
What most people get wrong
Two things: not doing it at all (very common with new campaigns), and over-blocking. Over-blocking happens when negatives are set too broadly and start cutting out relevant traffic. Add “free” as a broad match negative and you might inadvertently block “free quote” searches from people who are absolutely potential customers. Check the logic before adding anything broad-scope.
The other mistake is treating it as a one-off task. Search behaviour changes. Google updates how its matching works. What was an effective negative list six months ago may have gaps now. The search terms report is worth ten minutes of attention every week or two. It’s consistently one of the highest-leverage things you can do inside a Google Ads account.
