Start with the search terms report
Your keywords are what you bid on. The search terms report shows what people actually typed before your ad appeared, and the two can be surprisingly far apart, especially with broad match keywords.
Google does not show every search. Its help page explains that terms without enough query activity are left out for privacy reasons. What it does show is usually enough to spot the patterns, and patterns are what negative keywords are for.
The themes that waste trade budgets
Jobs and training
Jobs, vacancies, apprenticeship, salary, course, training, qualification. People looking for work in your trade search with the same words as your customers.
DIY and how-to
“How to”, DIY, yourself, video, tutorial. Add “how to” as a phrase rather than excluding the word “how”, because “how much does a new roof cost” is often a buyer.
Free, used and second hand
Free, second hand, used, and grant searches unless you install through a funded scheme. Think twice before excluding “cheap”: some price-conscious searchers are perfectly good customers.
Parts, products and retailers
Parts, spares, manuals, and the names of DIY retailers and trade counters. These are people buying materials, not hiring a tradesperson.
Words with another meaning
Every trade has them. Roof racks and roof tents for roofers. Tumble dryers and pool heaters for heat pump installers. Portable units and car air conditioning for air conditioning firms. Solar garden lights for solar installers. Car windows for glaziers.
Places you do not cover
Town names outside your area, and towns that share a name with somewhere else in the UK. Location targeting does most of this work, but searches that name a distant town can still slip through.
Services you do not offer
Commercial work if you only do homes, repairs if you only install, and any product you do not fit. Be specific: a roofer who does not clean roofs should exclude “roof cleaning”, not “cleaning” across every campaign.
How negative match types behave
Negative keywords do not work quite like normal keywords, and the differences cause most of the mistakes:
- Negative broad match blocks a search that contains all of your negative words, in any order.
- Negative phrase match blocks a search that contains your words in the same order, even with other words around them.
- Negative exact match blocks only that exact search, with no extra words.
Negative keywords also do not match close variants or synonyms. Excluding “job” does not exclude “jobs”, so add the singular and plural. Google says misspellings and capital letters are handled for you.
How not to overdo it
The danger with negative keywords is that the mistakes are silent. A search you block never appears in any report, so nobody notices the customers you lost. A few rules help:
- Never exclude a word you also sell. If you do repairs, “repair” cannot be a negative anywhere.
- Be careful with price words. “Price”, “cost” and “quote” are usually signs of a buyer.
- Prefer phrases to single words when a word has both good and bad uses.
- Put trade-wide exclusions, such as jobs and DIY, in a shared list, and keep service-specific ones at campaign level.
A routine that keeps the account clean
Review the search terms regularly, more often while an account is new or after any change to keywords or match types. Sort by cost, look for themes rather than single searches, and add each exclusion at the right level. Keep a note of what was added and why, so the next person to look at the account understands it.
We do this for every account we manage as part of Google Ads management, and the trade-specific pages in our industries section list the searches we exclude first for each trade.
Sources
- About negative keywords, Google Ads Help, checked 26 October 2026.
- About the search terms report, Google Ads Help, checked 26 October 2026.