When you choose keywords for a Google ad, it is natural to assume your ad shows for those words. It shows for a lot more than that. Google matches on meaning, not only on the exact words you typed, and the difference between what you chose and what you actually paid for is where most of the wasted money in a small contractor’s account lives.
Negative keywords are the control for that. They are unglamorous and they are the single most reliable way to make an existing budget go further, because every dollar they save was being spent on somebody who was never going to hire you.
For transparency: Reign AI manages Google Ads for clients, including negative keyword work, so this page is written by somebody who sells the service. Where it describes common practice rather than Google’s documented rules, it says so.
What a negative keyword does
A negative keyword tells Google not to show your ad for a search containing it. Google’s overview of negative keywords covers the mechanics; the idea is simple.
If you are an electrician bidding on “electrician”, you want “emergency electrician” and “electrician near me”. You do not want “electrician apprenticeship”, “electrician salary” or “how to wire a light switch”. Those people share your keyword and none of them are customers. A negative on “apprenticeship”, “salary” and “how to” keeps your ad away from them.
Why your ad shows for searches you never chose
This is the part most people underestimate. Matching is looser than it appears:
- Broad match shows your ad for searches Google considers related, which can be a long way from your words. It finds new customers and it finds a lot of waste.
- Phrase match requires the meaning of your phrase, with other words allowed around it.
- Exact match is closer, but it is not literally exact — Google can show an exact-match keyword for searches it reads as having the same meaning.
None of that is a flaw; it is how the system is designed to find customers you would not have thought to target. But it means the list of keywords you wrote is not the list of searches you are paying for. The second list is the one that matters.
The search terms report is where the waste shows up
Google’s search terms report lists the actual searches that triggered your ads. It is the only reliable place to find what you are paying for, and it is the source for almost every useful negative.
One honest limit, in Google’s own words: the report covers search terms used by a significant number of people. Low-volume searches may not appear individually, so it is the best view you have rather than a complete census.
How it is usually worked — this is common practice, not a Google rule:
- Sort by cost, highest first. The expensive waste is where the money is. Fix that before the long tail.
- Then scan by impressions. High-volume searches that are not yet costing much will be soon.
- Ask one question of each term: would this person hire me? Not “is this relevant to my trade” — relevant is not the same as a customer.
- Add the negative at the right level. A term that is wrong for one service goes on that ad group. A term that is wrong for the whole business goes on a shared list.
The themes that account for most of it
In a contractor account the waste clusters into a handful of recurring themes. Keeping each as a separate, named shared list is the common approach, and the reason is practical: if one list turns out to be blocking good customers, you can detach that one list in a single step instead of hunting through hundreds of individual entries.
- Job seekers — jobs, hiring, careers, salary, apprenticeship, training, course.
- Do-it-yourself — how to, DIY, tutorial, guide, video, instructions.
- Free and cheap — free, freebie, and carefully cheap (see below).
- Wrong service — the parts of your trade you do not do. A plumber who does not do well pumps.
- Informational — definitions, meaning, what is, symptoms.
- Wrong place — cities and regions you do not serve, if your location targeting is not doing it.
- Competitor brand names — a judgement call, covered below.
Where negatives go wrong
The risk with negative keywords is not adding too few. It is adding too many, too broadly, because over-blocking fails silently. There is no error message. There are just fewer customers, and nothing tells you why.
- “Cheap” is the classic trap. Blocking it removes people looking for affordable repairs, many of whom would book. Block it only if cheap work is genuinely not something you do.
- Blocking your own service by accident. A negative on “commercial” is fine for a residential-only plumber and a disaster for one who wants office buildings.
- Old negatives go stale. A service you did not offer last year may be one you do now. Reviewing the shared lists occasionally — not just adding to them — catches that.
- Competitor names are a choice, not a rule. Some businesses want to appear when people search for a competitor; others find those clicks convert poorly. Decide deliberately and keep it in its own list so the decision is reversible.
How often
Often enough that waste cannot pile up between checks. For an account spending steadily that usually means weekly; a quiet one can go longer. The honest rule is about match types: if you run looser matching, somebody has to read the search terms regularly, because that is the bargain broad match asks for. An account running broad match with nobody reading the report is paying for Google’s guesses without checking them.
What negatives do not fix
- They do not make a bad ad good. If the right people are seeing the ad and not calling, the problem is the ad, the landing page or the offer.
- They do not fix a phone that goes unanswered. A perfectly targeted click that ends in a missed call is still a lost job — the case in what missed calls actually cost.
- They cannot see which clicks became work. Negatives remove obvious waste; knowing which searches actually produced jobs needs call and conversion tracking, covered in call tracking for contractors.
- They are not a Local Services tool. Local Services Ads have no keywords at all — the equivalent controls there are job types and service area, described in Local Services Ads lead credits.
The wider question of which of these jobs is worth doing yourself and which to hand off is in Google Ads versus Local Services Ads.
Common questions
What is a negative keyword?
A word or phrase you tell Google not to show your ad for. If you add "jobs" as a negative, a search like "plumber jobs near me" will not trigger your ad even though it contains your keyword. Negatives are how you keep paying for customers and stop paying for everyone else who happens to type the same trade name.
Why is my ad showing for searches I never chose?
Because keyword matching is looser than it looks. Google matches on meaning, not only on the exact words, so even a keyword set to exact match can show for searches Google reads as the same intent. That is often useful — it catches phrasings you would never have thought of — but it also catches searches you would never pay for. The search terms report is where both kinds show up.
How often should I check the search terms report?
Often enough that waste cannot pile up between checks. For an account spending steadily that usually means weekly; a quiet account can go longer. The practical rule is that if you are running looser match types, somebody has to be reading the report regularly, because that is the trade those match types ask of you.
Can I add too many negative keywords?
Yes, and it is the failure nobody notices. An over-broad negative blocks good searches silently — there is no error, just fewer customers. Blocking "cheap" can remove people looking for affordable repairs who would have booked. Keep negatives narrow, group them in named lists, and look again at old ones occasionally, because a term that was waste last year can be a real customer this year.
Does the search terms report show every search I paid for?
No. Google says the report shows search terms used by a significant number of people, so low-volume searches may not appear individually. The report is the best view you have, but it is not a complete list of everything that triggered your ad.