Google Ads Negative Keywords: The Complete Guide for Australian Businesses
Google Ads negative keywords stop your ads showing for searches that will never turn into a customer. You add them at ad group, campaign or account level, and every one you add takes budget away from the wrong clicks and puts it back in front of buyers. For most Australian small businesses, negative keywords are the fastest way to cut cost per lead without touching bids or budget.
We have managed accounts where the same campaign, same budget and same ads produced completely different results three months apart, and the only thing that changed was the negative keyword list. One of our carpet cleaning clients in Sydney dropped their cost per lead from $108 to $70. Not from a clever bidding trick. From methodically clearing out irrelevant search terms every single week.
In this guide:
- What Negative Keywords Actually Do
- Where Your Budget Is Actually Leaking
- Negative Keyword Match Types
- Ad Group, Campaign or Account?
- The Starter Lists Most Australian Businesses Need
- How Often Should You Be Doing This?
- When Negative Keywords Work Against You
- Frequently Asked Questions
What Negative Keywords Actually Do (And What They Don't)
A negative keyword is a term you tell Google to exclude. When someone searches using that term, your ad does not enter the auction. That is the whole mechanic.
What they are not: a way to block competitors from outranking you, and not a substitute for good keyword selection. If your keyword list is too broad to begin with, negatives are you mopping the floor while the tap is still running. Fix the keyword structure first, which is covered in our complete guide to Google Ads for Australian businesses, then use negatives to catch what leaks through.
The other thing worth knowing early is that negative keywords do not behave like positive keywords. Positive keywords match close variants, plurals, misspellings and synonyms. Negative keywords do not. If you block "plumbing course" you have not blocked "plumbing courses". You need both.
Where Your Budget Is Actually Leaking
Open the search terms report. Campaigns, then Insights and reports, then Search terms. Set the date range to the last 90 days and sort by cost.
Do not sort by impressions or clicks. Sort by cost. You are looking for money, not activity.
What you will usually find in an Australian account falls into four buckets:
- Job seekers. Someone searching "electrician jobs Sydney" or "plumber apprenticeship" is not hiring you. This is one of the biggest sources of waste in trades accounts.
- DIY and free intent. "how to unblock a drain yourself", "free landing page builder", "DIY pest control". These people have already decided not to pay anyone.
- Wrong location. Local service businesses picking up searches from Auckland, Perth or an interstate suburb with the same name. Australia has a lot of duplicate suburb names and Google is not always careful about it.
- Wrong intent entirely. Your service name attached to a marketplace, a course, a wholesaler or a competitor's brand.
One thing to be careful about here. The search terms report only shows terms that meet Google's privacy threshold, so you are never seeing all of it. Judge patterns, not individual one-click terms. If a term cost you $4 once, that is noise. If a category of terms cost you $400 across 90 days, that is a problem. Ignoring this report for months is one of the most common Google Ads mistakes we see Australian businesses make.
Negative Keyword Match Types: The Part Most People Get Wrong
There are three, and the default is broad. Most people never change it and then wonder why things are still slipping through.
- Negative broad match (carpet cleaning course) blocks any search containing all of those words in any order. It does not block plurals, misspellings or synonyms.
- Negative phrase match ("carpet cleaning course") blocks searches containing that exact phrase in that order, with other words allowed either side.
- Negative exact match ([carpet cleaning course]) blocks only that search, exactly as written, and nothing else.
In practice, single words at broad match do most of the heavy lifting. Blocking job, jobs, salary, course, courses, free and DIY at broad match will clear out a huge amount of rubbish in one afternoon. Google's own documentation on negative keywords confirms the matching rules if you want to check the fine print.
The trap: broad match negatives are blunt. Block "free" and you also block "free quote", which for a lot of service businesses is a genuinely high-intent search. Before you add a single word negative, search the report for that word and see what else it is attached to. Ten minutes of checking saves you from switching off leads you wanted.
Ad Group, Campaign or Account: Where Should Negatives Sit?
The level you choose changes how much control you keep.
Ad group level is for sculpting between your own ad groups. If you have separate ad groups for "emergency plumber" and "hot water system replacement", you add each ad group's terms as negatives in the other so the right ad shows for the right search.
Campaign level is for anything that should never trigger that campaign. Wrong locations, wrong services, wrong intent. Each campaign holds up to 5,000 negative keywords, which is far more than you will ever need.
Account level and shared lists are for the universal stuff. Job seekers, courses, competitor names you never want to bid on. Build one list, apply it to every campaign, update it once. Account level negatives also carry across to Performance Max, which matters if you are running Shopping through a Performance Max campaign and watching search terms you cannot control as tightly.
If you are not sure, start at campaign level. It is the easiest to audit later, and audit-ability matters more than elegance when someone else has to pick up the account.
The Starter Lists Most Australian Businesses Need
Every account is different, but these are the categories we build first for almost every client.
- Employment: job, jobs, career, careers, salary, wage, hiring, apprenticeship, TAFE, resume, seek
- Education and DIY: course, courses, training, certificate, how to, tutorial, DIY, yourself
- Free and cheap: free, freeware, cheapest, bargain (check "free quote" before you block "free")
- Marketplaces and directories: gumtree, airtasker, hipages, oneflare, ebay, facebook marketplace, yellow pages
- Wrong geography: NZ, New Zealand, Auckland, UK, USA, plus any Australian state or city you do not service
- Research intent: reviews, complaints, scam, wikipedia, reddit, meaning, definition
For lead gen businesses, add wholesale, supplier, manufacturer and bulk. For eCommerce, add anything describing a product you do not stock, along with second hand, used and repair if you only sell new.
How Often Should You Actually Be Doing This?
Weekly for the first two months of a new campaign. Then fortnightly. Then monthly once the account has settled and the search terms report stops surprising you.
New campaigns need the most attention because Google is still working out who to show you to, and that early period is where the majority of waste happens. A north-west Sydney appliance repairer we work with generated 123 leads over five months at $63 a lead, and 80% of those leads converted into paid jobs. That efficiency came from the front end being tight before we scaled spend into it, not from finding a magic keyword.
Set a recurring calendar block. Fifteen minutes a week beats a three hour cleanup every quarter, because in that quarter you have already spent the money.
When Negative Keywords Start Working Against You
This is where people go too far.
Over-negating starves smart bidding. If you are running Maximise Conversions or Target CPA, the algorithm learns from conversion data, and every negative you add narrows the pool it can learn from. Choke it too hard and you get a campaign that is very efficient and delivers four leads a month.
Watch for three warning signs. Impressions dropping sharply with no lift in conversion rate. A rising number of "eligible (limited)" statuses. And conflicts, where a negative you added is blocking one of your own active keywords. Google flags these under Keywords, then Negative keywords, but only if you go looking. Sustained low impression volume also affects your Quality Score over time, because expected click-through rate needs data to be calculated from.
The rule we use: negate what is clearly wrong, leave what is merely unproven. A search term with no conversions and eight clicks is not proof of anything. A search term with no conversions and sixty clicks is.
Frequently Asked Questions About Google Ads Negative Keywords
How many negative keywords should I have?
There is no correct number. Small local service accounts commonly sit between 50 and 300. What matters is whether each one was added for a reason you could explain out loud. A 2,000 keyword list copied from a blog post is worse than 40 you chose from your own search terms report.
Do negative keywords work with Performance Max campaigns?
Yes. Account level negative keywords apply across Performance Max, and campaign level negative keyword lists are supported as well. It is still less granular than Search campaigns, so the account level list does most of the work.
Will negative keywords lower my cost per click?
Not directly. They lower your cost per lead by removing clicks that were never going to convert, which is a different thing. Your CPC may even go up slightly as the remaining traffic gets more competitive, and that is usually fine if the conversion rate rises with it.
Should I add my competitors' brand names as negative keywords?
Usually yes, unless you are deliberately running a competitor campaign with its own budget and its own landing page. Competitor traffic converts at a lower rate and costs more, so if it is bleeding into your main campaign uninvited, block it.
Can negative keywords hurt my Quality Score?
Not on their own. But if you negate so heavily that your keywords stop getting impressions, you lose the data that expected click-through rate is built on, which affects Quality Score indirectly.
Stop Paying for Searches That Were Never Going to Convert
Most accounts we audit have a meaningful share of spend going to search terms the business owner would reject instantly if you read them out loud. The fix is not complicated. It is just consistent, and consistency is the part that falls over when you are running the business as well.
If you would rather have someone doing this every week without you thinking about it, that is a large part of what our Google Ads management work actually is. No lock-in contracts, and you talk directly to the person running your campaigns.