Broad and phrase match keywords are useful right up until they start pulling in searches you would never bid on: “free”, “jobs”, “diy”, a competitor’s brand, the wrong intent entirely. Every one of those clicks is money you will not get back. Negative keywords are the fix - they tell Google Ads which searches should never trigger your ads. The hard part was never the concept. It is finding the right terms fast, adding them at the right level, and not accidentally blocking a keyword that was actually working.
This is a walkthrough of doing that well, and where a negative keyword tool saves you the tedious parts.
What negative keywords actually do
A negative keyword stops your ad from showing on searches that contain that term. Add “free” as a campaign negative and any query with “free” in it drops out of the auction for that campaign. That is it - no bid, no click, no charge.
The reason they matter so much is that a handful of junk terms can quietly eat a real slice of a budget. You are not just wasting the click cost; you are dragging down your click-through rate and conversion rate on the data Google uses to decide how to spend the rest of your money. Cleaning up search terms is one of the highest-leverage things you can do in an account, which is why Keyword Ninja’s Wasted Spend analysis is free on every plan.
Find candidates from your real search terms
Guessing at negatives is a waste of time. The good candidates are already sitting in your search-terms report - the actual queries people typed to reach your ads. You want the ones spending money and returning nothing.
Keyword Ninja’s search-term mining flags exactly these. A term becomes a negative candidate when it has enough history to trust (at least 5 rows of data), zero conversions, and at least $10 in cost. That last threshold matters: a term with two clicks and no conversions is noise, not a decision. Waiting for real spend before you act keeps you from cutting terms that simply had not been given a chance yet.
There is one guardrail that saves you from a classic mistake: the miner never suggests a negative that would block one of your enabled keywords. If a search term matches a keyword you are actively bidding on, it stays off the negative list. More on why that matters below.
You can review these two ways:
- The search terms table - a sortable, filterable view for working through a lot of terms at once.
- Search Terms Ninja - a swipe deck that shows one term at a time. Swipe left to add it as a negative, right to add it as a keyword. It is fast, and it is genuinely the quickest way to clear a backlog. The full walkthrough is here.
Either way, your decisions stage into a queue and get applied to Google Ads in one batch rather than one painful edit at a time.
Exact, phrase, and broad negatives
Negatives have match types too, and they behave differently from positive keywords - this trips people up.
- Exact negative blocks only that exact search.
[running shoes]as an exact negative stops “running shoes” but not “best running shoes”. Use it when you want to surgically remove one query. - Phrase negative blocks any search containing that phrase in order. “running shoes” as a phrase negative stops “best running shoes” and “running shoes for men”. Use it for a phrase that is reliably bad wherever it appears.
- Broad negative blocks searches containing all the words in any order. Use it carefully - it catches the widest net and is the easiest way to block more than you meant to.
Keyword Ninja defaults new negatives to EXACT, which is the safe choice: it removes exactly the term you reviewed and nothing you did not look at. Reach for PHRASE when you have spotted a pattern - a word or phrase that is bad every time it shows up. That kind of pattern-spotting is what N-gram analysis is built for; it breaks your search terms into individual words and phrases so you can see, for example, that every query containing “cheap” loses money.
Campaign level vs ad group level
Where you add a negative decides how far it reaches.
- Campaign-level negatives apply to the whole campaign. Use them for terms that are wrong for the entire product or offer - “free”, “jobs”, competitor brands, informational intent when you only sell.
- Ad-group-level negatives apply to one ad group. Use them to steer traffic between ad groups rather than block it outright - keeping “women’s” searches out of your men’s ad group, for instance, so each group serves the query it is built for.
Keyword Ninja supports both, so you can block broadly wrong terms at the campaign and shape intent at the ad group.
There is a nice touch worth knowing about here. When you promote a search term into a brand-new ad group, the tool automatically adds that same term as an EXACT negative to the original ad group. That stops the old and new ad groups from bidding against each other on the same query - self-cannibalization you would otherwise have to remember to prevent by hand.
The trap: blocking a keyword you actually want
Here is the failure mode that quietly costs accounts real volume. You add a negative to clean up waste, and it also blocks an enabled keyword you are paying to run. The keyword stops serving, impressions vanish, and nothing in the interface shouts at you about it. You just slowly lose traffic and wonder why.
This happens because negative match types overlap with your positive keywords in ways that are easy to miss - a broad negative sharing a word with a live keyword, a phrase negative catching a keyword you forgot about.
Two things guard against it. First, as noted, the miner refuses to suggest a negative that would block one of your enabled keywords in the first place. Second, the Conflicts view scans your existing negatives against your active keywords and surfaces every case where a negative is blocking a live keyword - exact, phrase, or broad. If you have ever added negatives in bulk and later lost impressions for no obvious reason, this is where you find out why. The conflicts guide covers how to read and clear them.
Automating it
Once you trust your thresholds, you can stop doing this by hand. Keyword Ninja’s ADD_NEGATIVE_KEYWORD automation rule (available on PRO and up) runs daily and adds negatives for search terms that have hit at least 20 clicks with zero conversions - a defensible “this has had its chance and failed” bar. It defaults to EXACT match and caps itself at 25 negatives per run so a bad day of data cannot nuke your account. It is a floor of hygiene that runs whether or not you log in.
Manual in Google Ads vs a tool
You can do all of this inside Google Ads directly, and for a small account it is fine. Open the search terms report, sort by cost, eyeball the junk, and add negatives one at a time. Nothing wrong with it.
It stops scaling quickly, though. Google Ads will not tell you a negative you are about to add blocks a live keyword. It will not batch your decisions, mine candidates against sensible cost and conversion thresholds, or run the cleanup on a schedule. You end up reconstructing all of that by hand, every week, across every campaign. A negative keyword tool exists to collapse that into a few minutes: the candidates are pre-filtered, the conflicts are flagged before they bite, and the changes apply in one pass.
For the wider picture of where accounts leak money, 5 signs you’re wasting Google Ads budget walks through the other common culprits.
See what your account is leaking
You do not have to take any of this on faith. Run a free audit - no credit card, read-only access to your account, results in minutes. It surfaces the zero-conversion terms, the waste, and the negatives worth adding, so you can decide what to cut before you spend another dollar on searches that were never going to convert.