Negative keywords explained - match types, list structure, a starter negative keyword list, and a monthly search-term review process. This guide is written for Advertisers cutting wasted spend from search campaigns, and everything below comes from work we do on live accounts rather than recycled theory. Skim the sections, take the numbers as starting benchmarks for your own market, and treat the checklist items as a work plan you can hand to your team or your agency this week.
What it costs
This is free work with immediate returns. In accounts we audit, a disciplined negative keyword programme typically recovers 10-30% of search spend that was buying non-commercial queries.
Treat every range above as a starting benchmark, not a quote. Competition in your specific market, the current state of your website, how much production capacity you already have in-house, and how aggressive your growth target is will all move the number. The useful exercise is to work backwards from revenue: what is one additional customer worth, how many do you need per month to justify the spend, and does the plan on the table plausibly produce them?
How long it takes
Build a starter list before launch, then review search terms weekly for the first month and monthly after. Negative keyword work is never finished because query patterns keep shifting.
Two things reliably compress timelines. The first is production volume: more genuinely useful pages and more consistent execution per month means faster results, which is why budget and speed are linked. The second is starting condition - a site with clean technical foundations and existing authority moves much faster than a new domain. Be honest about which one you are, then set expectations accordingly with whoever signs off on the budget.
What actually works
Understand the match types: broad negative blocks any query containing all the words in any order; phrase negative blocks the exact sequence; exact negative blocks only that precise query. Broad negatives are powerful and easy to over-apply.
Use shared negative lists at account level for universal blocks - jobs, careers, salary, free, cheap, DIY, torrent, template, course, wikipedia, reddit (unless relevant), sample, pdf, internship - then campaign-level lists for intent separation.
None of these are clever. They are the boring fundamentals executed at unusual quality and consistency, which is what separates programmes that compound from programmes that plateau after one quarter.
Cross-negate between campaigns so brand, generic and competitor traffic stays in its intended campaign and bidding stays comparable.
Review the search terms report by spend, not by impressions. The expensive irrelevant queries are the ones costing money.
Mistakes that cost the most
Adding a broad negative like 'free' when your offer is a free consultation, silently killing your best converting queries.
Only adding negatives at ad group level, so the same waste recurs across the account.
Assuming Smart Bidding or Performance Max removes the need - automated campaigns still need exclusions, and PMax needs account-level negative lists.
Every one of these is common enough that we expect to find at least two of them in any audit. Fixing them costs almost nothing compared with the spend they waste, so they belong at the top of the work plan rather than in a backlog.
Your next 90 days
Weeks 1-2: instrument everything first. Tracking, call tracking where relevant, a conversion definition that finance would accept, and a baseline you can defend later. Skipping this step is the single most expensive shortcut available, because without a baseline you cannot prove anything worked.
Weeks 3-8: ship the highest-leverage items from the 'what actually works' list above, in priority order, one at a time so each change stays attributable. Resist the urge to rebuild everything at once - it feels productive and it destroys your ability to learn.
Weeks 9-12: build the compounding layer - content cadence, review velocity, link acquisition, experimentation - and set a monthly review with a fixed agenda. Search-term reviews prioritised by spend consistently surface a small number of queries responsible for most waste - which is why spend-sorted review beats impression-sorted review.
If you would like a second opinion before you commit budget, we run free 30-minute strategy calls and will walk through your current setup using the same diagnostic we use with paying clients.
Ready to put this into action?
Book a free 30-minute strategy call. We'll audit your setup and share a clear plan.