Negative keywords are the underappreciated side of Google Ads management. Most guides focus on what you target. Negative keywords define what you exclude. Both decisions directly affect your cost per result, but exclusions get far less attention because they are less intuitive and less visible in the campaign dashboard.
The logic is simple. Your ad budget is finite. Every time your ad shows for a search from someone who would never hire you or buy from you, that is a portion of your daily budget that cannot go toward someone who might. Negative keywords prevent those irrelevant impressions, concentrating your spend on the searches most likely to produce real business outcomes.
How negative keywords actually work
A negative keyword is a word or phrase you add to tell Google: if this term appears in someone's search query, do not show my ad. Like regular keywords, negatives have match types. Negative broad match excludes searches containing all the words in your negative keyword term in any order. Negative phrase match excludes searches containing your exact phrase. Negative exact match excludes only searches that exactly match the term.
For most small business accounts, negative phrase match is the most useful. It gives you precision without requiring you to list every possible form of a word. Adding the negative phrase "how to" prevents your ad from showing for "how to fix a leaky tap," "how to unclog a drain," and hundreds of similar informational queries in one addition.
Negative keywords can be added at the campaign level (affecting all ad groups in that campaign) or at the ad group level (affecting only one specific ad group). In most cases, campaign-level negatives are the right place for universal exclusions. Ad group-level negatives are useful when you need to prevent overlap between ad groups targeting similar but distinct audiences.
Building your first negative keyword list
Before you launch a campaign, there are categories of terms you can add as negatives based on the type of business you run, without waiting for data.
The intent-wrong category covers people looking for DIY solutions, information, or products rather than services. Terms to add immediately: "free," "DIY," "how to," "yourself," "tutorial," "guide," "video," "template," "example," "sample," "download." These capture searchers who are researching, not buying.
The employment category covers people looking for jobs, not services. Add: "jobs," "career," "vacancy," "salary," "apprenticeship," "training course," "certification." A search for "electrician jobs Amsterdam" is from a job seeker. Your ad appearing there wastes budget and likely frustrates both parties.
The competitive-irrelevant category covers adjacent terms that share words with your keywords but refer to something different. A company offering IT support for businesses should add "support group," "mental support," and "emotional support" as negatives. A tax accountant should add "tax calculator" and "tax return software" to separate their service offer from software products. These seem obvious in retrospect but are easy to miss before you see them in your data.
Using the Search Terms report to build negatives from real data
Pre-launch negatives are a starting point. The more powerful source is your actual search term data after campaigns have been running for a few weeks. The Search Terms report (available under Keywords in your Google Ads interface) shows the real queries that triggered your ads, not just the keywords you targeted. This distinction is important: your keyword might be "boiler repair Utrecht" in phrase match, but the actual searches triggering it could include "boiler repair Utrecht forum," "boiler repair Utrecht cost estimate free," and "who does boiler repair Utrecht." Each of those is a different intent and a different quality of potential customer.
Sort the Search Terms report by cost, descending. Look at the highest-spend queries where no conversion was recorded. Ask whether those queries were from people who could realistically be your customers. If the answer is no, add them as negatives immediately. This monthly review is one of the highest-ROI tasks in Google Ads management. In new campaigns, the first two or three reviews typically recover 15-25% of budget that was going to irrelevant searches, putting it back toward the queries that actually convert.
Negative keyword lists for multiple campaigns
If you run multiple campaigns, managing negatives one by one in each campaign becomes tedious. Google Ads lets you create shared negative keyword lists that can be applied across campaigns simultaneously. Build a master exclusion list with your universal negatives (intent-wrong, employment, irrelevant adjacent terms) and apply it to all your search campaigns. When you find a new irrelevant term through your search term review, adding it once to the shared list applies the exclusion everywhere.
This matters especially when you are growing from one campaign to several. The time spent building and maintaining a solid shared negative list in the early months pays dividends as your account complexity increases.
When aggressive negative keyword lists go wrong
Negative keywords are not a set-and-forget tool. Adding too many negatives, or negatives that are too broad, can accidentally block searches from genuine customers. This is worth taking seriously. If you add "free" as a negative and your service genuinely includes a free initial consultation, you may be blocking searches like "free consultation plumber" that represent exactly the type of high-value prospect you want.
Before adding any negative keyword, ask whether there is a realistic version of that search that your ideal customer could make. If the answer is yes, use a more specific phrase rather than the broad term. "Free estimate" is safer to negate than "free" alone, because it excludes the freebie-seeker while preserving searches from someone researching whether you offer free consultations.
Similarly, watch your impression volume after adding significant negative lists. A sudden drop in impressions that is not explained by budget constraints or seasonal variation often indicates an over-aggressive exclusion that is blocking legitimate traffic. Negative keywords are not about minimising spend at all costs. They are about concentrating spend on the right searches.
How often to update your negative list
For a new campaign, review your Search Terms report weekly for the first month. After that, monthly reviews are sufficient for most small business campaigns. The volume of new irrelevant terms appearing tends to decrease over time as your match types and existing negatives do more of the filtering work. If you introduce a new ad group or new broad match keywords, increase your review frequency temporarily for that portion of the account.
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