Negative Keywords in PPC: The Secret to Cutting Wasted Ad Spend

What Are Negative Keywords?

Negative keywords are words or phrases you add to your PPC campaigns to prevent your ads from showing for irrelevant searches. They are the opposite of regular keywords. While regular keywords tell Google when to show your ads, negative keywords tell Google when not to show them.

For example, if you run an accounting firm targeting “accounting services Singapore”, your ads might also show for searches like “free accounting services”, “accounting job Singapore”, or “accounting course Singapore”. None of those searchers are your customers, but every click from them costs you money.

By adding “free”, “job”, and “course” as negative keywords, you stop your ads from appearing for those irrelevant searches. Your budget goes entirely toward people who are actually looking for what you sell. It is one of the most powerful levers in SEM campaign management, and it is the one most businesses neglect.

Think of negative keywords as a filter that keeps your ad spend pure. Without them, you are paying for traffic that will never convert. With them, every dollar works harder because it only reaches people with genuine purchase intent.

How Much Money Are You Wasting Without Negative Keywords?

More than you think. In our experience managing campaigns for 146+ clients at Best Marketing, we typically find that 20 to 30% of a campaign’s clicks come from irrelevant searches when negative keywords are not properly managed. On a $5,000 monthly ad budget, that is $1,000 to $1,500 going straight down the drain every single month. Over a year, that is $12,000 to $18,000 in pure waste.

It gets worse. Those wasted clicks do not just cost you money directly. They also hurt your campaign metrics in ways that compound over time. Your click-through rate drops because your ads are showing to the wrong people. Your conversion rate drops because irrelevant visitors never convert. And as those metrics decline, Google lowers your Quality Score, which raises your cost per click because it sees your ads as less relevant.

It is a vicious cycle. But adding the right negative keywords breaks that cycle immediately. We have seen clients cut their cost per lead by 30 to 50% just by cleaning up their negative keyword lists. That is more leads for the same budget, or the same leads for significantly less money.

One Singapore renovation company we took over was spending $8,000 per month on Google Ads with a $210 cost per lead. After adding 127 negative keywords in the first week (terms like “DIY”, “course”, “salary”, “job”, “free”, “cheap”, and various irrelevant service types), their cost per lead dropped to $89 within 30 days. Same budget, same landing page, same ads. The only change was telling Google which searches to ignore.

What Are the Different Negative Keyword Match Types?

Just like regular keywords, negative keywords have match types that control how broadly they block searches. Understanding these match types is essential for avoiding both wasted spend and accidentally blocking relevant traffic:

• Negative broad match (default): Blocks your ad if the search contains all the negative keyword terms in any order. Adding “free course” as a negative broad match blocks “free accounting course” and “course for free” but does not block “free accounting template” because “course” is missing.
• Negative phrase match: Blocks your ad if the search contains the exact phrase in order. Adding “free course” as negative phrase match blocks “best free course in Singapore” but does not block “free accounting course” because the words are not in the exact phrase order.
• Negative exact match: Only blocks the exact search query with no additional words. Adding [free course] only blocks the search “free course” and nothing else. “Free accounting course” would still trigger your ad.

For most situations, negative broad match is the safest default. It casts the widest net and prevents the most irrelevant clicks. Use phrase and exact match when you need more precision to avoid accidentally blocking searches from legitimate prospects.

One important nuance: negative keywords do not recognise close variants the way positive keywords do. If you add “free” as a negative, it will not automatically block “freebie” or “for free”. You need to add those variations separately. This is a common blind spot that lets wasted spend slip through.

How to Find Negative Keywords for Your Campaigns

The best source of negative keywords is your own campaign data. Here is our systematic process for finding them:

Search terms report. This is your primary weapon. In Google Ads, go to Keywords, then Search terms. This shows you the actual queries people typed before clicking your ad. Review this weekly, not monthly. We review search terms reports for every client every seven days because irrelevant clicks accumulate fast. Add any irrelevant terms as negative keywords immediately.

Brainstorm before launch. Before you even start a campaign, think about the obvious irrelevant terms. If you sell premium products, add “cheap”, “free”, “budget”, and “discount”. If you are a service business, add “DIY”, “template”, “course”, and “tutorial”. This pre-launch list saves you money from day one.

Common negative keyword categories to consider:

• Job-related terms: jobs, career, salary, hiring, vacancy, resume, internship, part-time
• Education terms: course, training, tutorial, how to, certification, degree, diploma, university
• Free-seeker terms: free, cheap, budget, discount, sample, trial, open source
• DIY terms: DIY, template, software, tool, calculator, spreadsheet, download
• Competitor brand names: Unless you are intentionally targeting competitor searches as part of a bidding strategy
• Irrelevant locations: If you only serve Singapore, add country names for markets you do not serve

Negative Keyword Lists: How to Stay Organised

Google Ads lets you create shared negative keyword lists that apply across multiple campaigns. This is far more efficient than adding negative keywords to each campaign individually, and it ensures consistency across your entire account.

We recommend creating these standard lists for every client account:

• Universal negatives: Terms that are irrelevant to your entire business regardless of campaign. Job-related terms, education terms, and free-seeker terms typically go here. Apply this to every campaign in your account.
• Industry-specific negatives: Terms specific to your industry that attract the wrong audience. A renovation company might add “commercial”, “office”, and “industrial” if they only do residential work.
• Location negatives: If you only serve Singapore, add country and city names for markets you do not serve. This is especially important for broad match campaigns that might trigger for Malaysian or Australian searches.
• Brand negatives: Competitor brand names you do not want to bid on (unless competitor targeting is part of your strategy).

Keep your lists updated. Set a recurring calendar reminder to review your search terms report every Monday morning. It takes 15 minutes but can save hundreds or thousands of dollars each month. The businesses that consistently manage their negative keywords are the ones that get the best returns from Google Ads, period.

Negative Keywords at the Ad Group Level

Most businesses only add negative keywords at the campaign level, but ad group level negatives are equally important for keeping your campaigns clean and your targeting precise.

Here is why. If you have separate ad groups within a campaign for “SEO services” and “web design services”, searches containing “web design” might trigger your SEO ad group and vice versa. This means the wrong ad shows for the wrong search, reducing relevance and hurting Quality Score.

The fix is simple: add “web design” as a negative keyword in your SEO ad group, and add “SEO” as a negative keyword in your web design ad group. This ensures each search query triggers only the most relevant ad group, improving both CTR and conversion rates.

This technique, sometimes called “ad group sculpting” or “traffic funnelling”, is standard practice for well-managed accounts. It is especially valuable when your business offers multiple services that share some keyword overlap, which is the case for most Singapore businesses running Google Ads.

At Best Marketing, we implement ad group level negatives for every campaign we manage. Combined with campaign level lists and proper budget allocation, this layered approach ensures every click reaches the right ad with the right message.

Common Negative Keyword Mistakes That Cost You Money

Not reviewing search terms regularly. This is the most common and most expensive mistake. If you set up a campaign and never check what searches are triggering your ads, you are guaranteed to waste money on irrelevant clicks. We have inherited accounts where 40% of the monthly spend was going to completely irrelevant searches because nobody checked the search terms report for months.

Being too aggressive. Adding too many negative keywords can reduce your reach dramatically and prevent your ads from showing for legitimate searches. Be careful not to block terms that real prospects might use. For example, blocking “cheap” might make sense for a luxury brand, but not for a budget-friendly service that competes on price.

Forgetting about close variants. Google matches negative keywords less broadly than positive keywords. If you add “free” as a negative, it will not block “for free” or “freebie” unless you add those separately. Build your negative keyword lists with variants in mind.

Only adding negatives at launch. Your initial negative keyword list is just the starting point. The real work happens over weeks and months as you review search terms data and continuously refine your lists. A mature campaign should have a negative keyword list that grows steadily over time.

If you want help auditing your Google Ads campaigns for wasted spend, book a free strategy session with our team. We have helped businesses across Singapore recover thousands of dollars in wasted ad spend through proper negative keyword management and complementary SEO strategies that reduce dependence on paid traffic over time.

Frequently Asked Questions

How many negative keywords should a campaign have?

There is no magic number. A well-managed campaign might have anywhere from 50 to 500+ negative keywords depending on the industry and keyword strategy. A new campaign typically starts with 30 to 50 pre-launch negatives and grows as you review search terms data weekly. The important thing is to review and update them regularly. Quality and relevance matter more than quantity.

Can negative keywords hurt my campaign performance?

Yes, if you add negative keywords that are too broad, you can accidentally block relevant searches and reduce your traffic. Always check the potential impact before adding a negative keyword by searching for it in your search terms report to see what it would have blocked. If you are unsure, start with negative exact match to be safe and broaden it later if needed.

Do negative keywords affect Quality Score?

Indirectly, yes. By blocking irrelevant clicks, negative keywords improve your click-through rate and conversion rate, which are factors in Quality Score. A higher Quality Score means lower cost per click and better ad positions. So negative keywords help your Quality Score by keeping your campaign focused on relevant, high-intent searches.

Should I add competitor names as negative keywords?

It depends on your strategy. If you are not intentionally bidding on competitor brand terms, adding them as negatives prevents your ads from showing to people searching specifically for a competitor. However, if you are running a deliberate competitor targeting strategy, you would want your ads to show for those searches. Decide your approach and be consistent across all campaigns.

How quickly will I see results after adding negative keywords?

Almost immediately. Negative keywords take effect as soon as they are added. You should see improvements in CTR and cost per conversion within the first week, with more significant cost per lead improvements becoming clear within two to four weeks as the cleaner data accumulates. It is one of the fastest-acting optimisations you can make in Google Ads.