The cheapest improvement available in a search account is not a better bid or a new landing page. It is a list of the searches you never want to pay for. Google Ads negative keywords take about half an hour a month to maintain and they stop money leaving before anything else has to work.
Most accounts I open have a nearly empty list. Not because anyone decided against it, but because nobody was assigned the half hour.
This is for you if your search campaigns are live and you have never built a proper exclusion list.
What Google Ads negative keywords do
They are the one direct control you keep over which searches your money goes to.
Your keywords tell Google what you want. Match types let Google interpret that generously. Negatives are how you say no, and they are the only instruction in the account that is absolute.
That matters more now than it used to. Broad match reaches further than it once did, and automated bidding will spend efficiently on whatever it is allowed to reach. Neither of those decides relevance. You do.
Where to add Google Ads negative keywords
Level is the part people get wrong, and it quietly costs them.
Account level is for anything irrelevant to your whole business. If you never sell to people looking for jobs, “careers” belongs here, once, and applies everywhere.
Campaign level is for terms that are wrong in one context and fine in another. A commercial campaign might exclude “free” while a lead magnet campaign depends on it.
Ad group level is for fine separation between closely related groups, and it is the level most people default to by accident. Burying an account-wide exclusion inside one ad group means the same waste simply reappears in the next campaign somebody builds.
Match types behave differently here
Negative match types are not a mirror of the positive ones, and this trips up experienced people.
Negative broad blocks any search containing all of your words, in any order. Phrase needs them in sequence. Exact blocks only that precise search and nothing else.
The important difference: negatives never match close variants. Positive keywords do. So blocking “recruiter” does not block “recruiters”, and blocking “colour” does not block “color”. Plurals, misspellings and spacing variants all need adding separately, which is why lists get long and why that length is fine.
Start with negative phrase for most things. It is specific enough to avoid collateral damage and broad enough to catch the variations that matter.
Building the list from your own data
Copying a list from an article is a poor substitute for reading your own report.
Open the search terms report, set it to the last 30 days, and sort by cost. Work down the expensive terms and mark the ones that could never convert. Those are your negatives, and they are already proven to have taken your money.
Look for themes rather than exact strings. If three variations of “how to do it yourself” appear this month, block the theme, because next month brings three different ones.
Then add the obvious intent mismatches even if they have not appeared yet: free, cheap, DIY, jobs, careers, salary, training, courses, and the name of anything adjacent that you do not actually sell.
Where Google Ads negative keywords can hurt you
They are a blunt instrument and it is possible to cut too deep.
Blocking “cheap” also blocks someone typing “cheap enough for a small business”, who might have been fine. Blocking a competitor’s name blocks comparison searches, which in some markets convert very well.
Large copied lists are the usual culprit. Half of a generic list will not apply to your business and a portion of it will exclude searches you wanted.
So if volume drops unexpectedly after a session, look at your recent negatives before you look anywhere else. It is a five-minute check and it is a common cause.
What this is worth in practice
The best search account on my books runs 6,070 leads at £11.40 each for a UK staffing and childcare business, in a competitive market.
The negative list is a large part of that, reviewed monthly rather than built once. Staffing attracts an enormous volume of job-seeker searches, and every one of those clicks is money spent on somebody who wants a job rather than somebody hiring.
For scale, WordStream’s 2026 study of 13,474 US search campaigns put the all-industry average at $66.69. Getting well under a figure like that is rarely about clever bidding. It is mostly about not paying for the wrong people in the first place.
The Google Ads negative keywords every account should start with
Before you have any data, there is a set that applies almost everywhere.
Intent mismatches come first. Someone searching “free”, “cheap”, “DIY” or “how to” is telling you they do not intend to pay. Someone searching “jobs”, “careers”, “salary” or “vacancies” wants employment rather than your service.
Learning intent is next. “Training”, “courses”, “certification” and “tutorial” all describe people who want to do it themselves. In some industries that is a large share of total search volume and none of it converts.
Then the adjacent things you do not sell. If you fit kitchens but not bathrooms, block bathrooms. If you serve businesses but not consumers, block the domestic words. This is where the biggest single savings usually sit, because these searches look relevant to a machine and are obviously wrong to you.
Add those, then let your own report build the rest. A starter list gets you most of the way in ten minutes. Your search terms get you the specific waste nobody could have predicted.
What to change this week
Four steps, about half an hour.
Open your account-level negative list and see whether it exists. If it is empty, that is your finding.
Pull the search terms report for 30 days, sorted by cost, and mark everything in the top twenty that could never convert.
Add those at the level they belong, using negative phrase unless you have a reason not to, and block themes rather than single strings.
Then add the standard intent mismatches for your industry, and put a recurring half hour in the calendar for next month.
The wider piece on judging lead cost covers what this feeds, reading the search terms report by hand is the source of every good negative, and fixing Performance Max lead quality covers where account-level negatives matter most. If you would rather this were simply done each month, Google Ads management includes it, and a teardown will show you what your list is missing.