What a Negative Keyword List Actually Does
A negative keyword tells Google "don't show my ad when someone searches this." That's it. No targeting magic, no algorithm trick — just a blunt instruction that stops a specific search from wasting an impression and a click.
Here's why that matters more than it sounds like it should. Google's broad and phrase match types are built to expand your reach, which means they'll happily show your roofing ad to someone searching "roofing jobs hiring" or "how to fix a roof yourself." Neither of those searchers is hiring you. Every click from them still comes out of your daily budget.
Say you run a plumbing company and you're bidding on "drain cleaning." Without negatives, that campaign will eventually show up for "drain cleaning jobs near me," "how to unclog a drain yourself," and "drain cleaning course." Three clicks, zero chance of a booked job. A negative keyword list is the filter that keeps those searches out entirely.
How to Build a Negative Keyword List for Google Ads From Scratch
Start with three sources before you spend a single new dollar:
- Your own Search Terms report. In Google Ads, open a campaign, go to Insights and Reports, then Search Terms. This shows the actual queries that triggered your ads — not the keywords you bid on, the real words a person typed. This is the single best source of negatives because it's built from your own data, not a guess.
- Obvious disqualifiers. Before you even launch, block the words that never convert for a service business: "jobs," "hiring," "salary," "career," "DIY," "how to [do it yourself]," "course," "training," "free," "template," "definition," "wikipedia." Add these at the account level so every campaign inherits them.
- Competitor and adjacent-service noise. If you sell HVAC installation, you don't want to pay for clicks on furnace repair only if that's not a service you offer, or for people searching a specific competitor's brand name.
Once you've got your list, add each term as a negative keyword at the campaign or ad group level (account-level negative lists are the more efficient option if you're running several campaigns with the same disqualifiers — Google Ads lets you build one shared list and apply it everywhere).
Match Types for Negative Keywords — Get This Wrong and You'll Block Good Traffic Too
Negative keywords have match types too, and mixing them up is the most common way small business owners accidentally block real customers.
- Negative broad match blocks any search containing all the words in the negative, in any order. Add "cleaning jobs" as negative broad and you'll also block "jobs cleaning offices" — probably fine, but check.
- Negative phrase match blocks searches containing that exact phrase, in that exact order, with other words allowed around it. "Drain cleaning jobs" as a negative phrase blocks "part time drain cleaning jobs" but not "jobs in drain cleaning."
- Negative exact match blocks only that precise search, nothing more, nothing less.
The safest default for disqualifying an entire category (jobs, DIY, free) is negative phrase. Reserve negative exact for narrow, specific terms you're certain you never want, since it won't accidentally catch a legitimate variation.
The Search Terms Report: Your Ongoing Source of New Negatives
Building the list once isn't the job — a negative keyword list built once and never touched again slowly goes stale as Google's matching expands what it thinks is "relevant." New irrelevant searches show up every week, especially on broad match.
Set a recurring 15-minute block, ideally weekly, to do exactly this:
- Open the Search Terms report for the last 7 days.
- Sort by clicks, not impressions — you want to see where money actually went.
- Scan every search term that got a click but zero conversions.
- For anything genuinely irrelevant to your business, add it as a negative right there in the report (Google Ads lets you do this in two clicks).
- Leave alone anything ambiguous — a search that's borderline but plausible is worth one more week of data before you cut it off completely.
This is also where you'll catch the searches you'd never have predicted. According to WordStream's 2025 Google Ads Performance study (251,236 reports across 15,666 accounts, January–November 2025), the average business wastes $1,127.54 a month in Google Ads spend against average monthly spend of $3,127.38 — roughly a third of the typical account's budget going to clicks that never convert. A weekly negative keyword pass is one of the more direct ways to claw part of that back.
When Not to Add a Negative
It's tempting to get aggressive and negative out anything that isn't a perfect match. Don't. Over-pruning shrinks your reach and can quietly choke off searches that would have converted with better ad copy or a landing page fix instead. Before adding a negative, ask: is this search irrelevant to what I sell, or is it relevant but just not converting yet? Only the first case belongs on the negative list — the second is a landing page or offer problem, not a targeting problem.
