The Google Ads auction, explained
Every time someone searches on Google, an auction runs in a fraction of a second to decide which ads appear and in what order. Only advertisers whose keywords match the search, and whose targeting includes that person's location, language and device, enter the auction.
Google then calculates an Ad Rank for each eligible ad. Ad Rank takes into account:
- Your bid: the maximum you're willing to pay for a click, set manually or by automated bidding.
- Ad quality: how relevant and useful your ad and landing page are likely to be for that search.
- Ad Rank thresholds: minimum quality levels an ad must meet to show in a given position.
- The context of the search: the terms used, location, device, time of day and other signals.
- The expected impact of assets: how much extras like sitelinks, callouts and images are likely to improve the ad.
The crucial point is that quality counts alongside money. An advertiser with a highly relevant ad and landing page can win a higher position than a competitor bidding more. That's Google's incentive at work: it earns more over time when searchers find ads useful.
What you actually pay
You pay only when someone clicks. The amount you pay, your actual cost per click, is usually less than your maximum bid. Broadly, it's the amount needed to hold your position above the next advertiser and clear the relevant thresholds. Better quality therefore lowers your costs as well as improving your position.
Quality Score: the number that affects everything
Quality Score is a diagnostic rating from 1 to 10 that Google shows for each keyword. It's based on three components:
| Component | What it measures | How to improve it |
|---|---|---|
| Expected click-through rate | How likely people are to click your ad for that keyword | Write specific, benefit-led ads that closely match the search |
| Ad relevance | How closely your ad matches the intent behind the keyword | Group tightly related keywords together and use their language in the ad |
| Landing page experience | How relevant, useful and easy to use your landing page is | Send traffic to a fast, specific page that delivers what the ad promised |
Quality Score itself isn't used directly in the auction, but it reflects the same quality signals that are. Treat low scores as a warning sign that you're paying more than you need to.
Google Ads campaign types
Google offers several campaign types, each showing ads in different places. Most businesses need only two or three.
| Campaign type | Where ads appear | Best used for |
|---|---|---|
| Search | Google search results | Capturing high-intent searches with precise keyword control |
| Performance Max | Search, Shopping, YouTube, Display, Gmail, Discover and Maps | Broad, automated reach, especially for e-commerce with good conversion data |
| Shopping | Product listings with images and prices | Online stores with a Merchant Center product feed |
| Demand Gen | YouTube, Discover and Gmail | Visual campaigns that create interest and build audiences |
| Video | YouTube and video partners | Awareness and consideration through video |
| Display | Websites and apps in the Google Display Network | Remarketing and controlled visual reach |
For most lead-generation businesses, Search is the best starting point because it reaches people actively looking. E-commerce stores usually combine Shopping or Performance Max with Search.
Keywords, match types and negative keywords
Keywords tell Google which searches your ads should be eligible for. Match types control how closely a search must match your keyword.
- Broad match (e.g. accounting software) can show your ad for searches related to your keyword, including ones that don't contain the words. It offers the most reach and works best with automated bidding and good conversion data, but needs careful monitoring.
- Phrase match (e.g. "accounting software") shows your ad for searches that include the meaning of your keyword, with words possibly added before or after.
- Exact match (e.g. [accounting software]) shows your ad for searches with the same meaning or intent as your keyword. It gives the most control and least reach.
A company selling accounting software to small businesses bids on "accounting software" in broad match. Without negative keywords, its ads may appear for "free accounting software download", "accounting software jobs" and "accounting software course". None of those searchers are likely buyers.
Adding negatives such as free, jobs, course and salary stops those clicks. Reviewing the search terms report weekly catches new irrelevant queries as they appear.
Negative keywords are just as important as the keywords you bid on. They prevent your ads showing for searches you don't want, and they're one of the fastest ways to cut wasted spend.
Choosing keywords by intent
Not all searches are equal. "What is payroll software" is research. "Payroll software pricing" or "best payroll software for startups" is closer to a decision. "Payroll software demo" is ready to act. Start with keywords closest to purchase, then expand once those are profitable.
Ads and assets
Search ads today are mostly responsive search ads: you provide up to 15 headlines and 4 descriptions, and Google tests combinations to find what performs best for each search. Good responsive ads include:
- Headlines that repeat the searcher's language, such as the keyword theme of the ad group.
- Specific benefits and proof: "Setup in 1 Day", "4.8★ from 500 Reviews" (only if true), "Free Consultation".
- A clear call to action.
- Variety, so Google has genuinely different options to test.
Assets (previously called extensions) add extra information: sitelinks to other pages, callouts, structured snippets, call buttons, location, images and prices. They make ads larger and more useful, and they contribute to Ad Rank, so it's worth adding every relevant type.
Already running Google Ads? We'll review your account and show where budget is being wasted.
Get a Free Account ReviewBidding strategies
Your bidding strategy tells Google what to optimise for. Most accounts now use automated "Smart Bidding", which sets bids for each auction using signals like device, location, time and audience.
| Strategy | Optimises for | When to use it |
|---|---|---|
| Manual CPC | Your own bids per keyword | Very small accounts or specific control needs |
| Maximise clicks | As many clicks as possible within budget | Gathering initial data; rarely for long |
| Maximise conversions | As many conversions as possible within budget | New campaigns with working conversion tracking |
| Target CPA | Conversions at an average target cost | Lead generation once you have steady conversion volume |
| Maximise conversion value | The highest total conversion value within budget | E-commerce or leads with different values |
| Target ROAS | Conversion value at a target return on ad spend | E-commerce with reliable revenue tracking and volume |
Smart Bidding is only as good as your conversion tracking. If it counts page views or duplicate form fills as conversions, it will efficiently buy more of the wrong thing. Setting up accurate conversion tracking, including enhanced conversions and importing qualified leads or sales from your CRM, is the single most valuable improvement most accounts can make.
Automated bidding also needs data. Campaigns with very few conversions a month struggle to learn. Consolidating campaigns rather than splitting budget across many small ones usually helps.
Default settings that often waste money
Google's default settings are designed to maximise reach. That's not always the same as maximising your results. Check these before launching:
- Location targeting "presence or interest". The default can show ads to people outside your area who are merely interested in it. Local businesses usually want "presence" only: people in or regularly in the location.
- Display Network expansion on Search campaigns. New Search campaigns may include Display placements by default, which behave very differently from search. Turn it off unless you want it.
- Search partners. Worth testing, but monitor performance separately and switch off if quality is poor.
- Auto-applied recommendations. Some recommendations can be applied automatically, including adding keywords or changing bids. Review which are enabled.
- Broad match without negatives or Smart Bidding. A recipe for irrelevant clicks.
- Brand terms in Performance Max. Without brand exclusions, PMax can spend on searches for your own name that you'd likely win cheaply anyway.
Setting up your first campaign: step by step
- Set up conversion tracking for enquiries, calls or purchases, and test it.
- Choose a Search campaign with a clear goal and a daily budget you're comfortable spending for at least a month.
- Set locations, languages and schedule to match where and when you can serve customers.
- Build tightly themed ad groups, each with a small set of closely related keywords.
- Add negative keywords from the start: jobs, free, training and other irrelevant intents.
- Write responsive search ads with varied headlines and add all relevant assets.
- Send each ad group to the most relevant page, ideally a dedicated landing page.
- Start with Maximise conversions once tracking works, then move to Target CPA as conversions accumulate.
- Review search terms weekly and adjust keywords, negatives, ads and budgets.
How to measure Google Ads success
Clicks and impressions show activity, not results. The numbers that matter are conversions, cost per conversion, conversion value and, ideally, how many conversions became customers. Connect Google Ads to GA4 and your CRM so you can see cost per qualified lead or return on ad spend by campaign and keyword. Our performance marketing guide covers these metrics in detail.
Frequently asked questions
How much does Google Ads cost?
You set your own budget and pay per click. Costs per click vary widely by industry, competition and location. Highly competitive sectors can be very expensive, while niche or local terms can be affordable.
Does the highest bidder always win?
No. Ad Rank combines your bid with ad quality, landing page experience, context and asset impact. A more relevant ad can outrank a higher bid.
How quickly do Google Ads work?
Ads can start showing within hours of approval. Automated bidding usually needs a learning period of a couple of weeks, and most campaigns take four to eight weeks to settle.
What is a good Quality Score?
Scores of 7 or above generally indicate good relevance. Low scores on important keywords suggest improving ad relevance or the landing page.
Should I use broad match keywords?
Broad match can work well with Smart Bidding and accurate conversion data, but it needs close monitoring and strong negative keywords. Many accounts start with phrase and exact match, then test broad.
Do Google Ads help SEO?
Not directly. Paid and organic rankings are separate. But search term data from ads is valuable for choosing SEO targets. See our comparison of SEO vs PPC.
Conclusion
Google Ads rewards relevance as much as budget. The businesses that do well with it build tightly themed campaigns around buyer intent, block irrelevant searches, write ads that match what people are looking for, send clicks to pages that deliver on the ad's promise, and give automated bidding accurate conversion data. Then they review and refine every week. Do those things consistently, and Google Ads becomes one of the most dependable ways to reach customers at the moment they're ready to buy.