How Google Ads Keyword Matching works

Table of Contents

In this Blog, I’ll take you behind the scenes and walk through how Google Ads keyword-matching solutions work. You’ll learn what signals are used, how queries match to keywords, how automation makes keyword matching more effective, and what you can do to improve performance.

How Google Ads keyword matching works

Our query systems are optimized to find searches that are likely to meet your goals. We’ve designed these solutions to work better together in an ecosystem, so you can reach the right user, with the right message, all within your business objectives. The process that takes a user from typing in a search, to matching your keyword, then seeing your ad, follows these core steps:

Step 1

When a user enters a search on Google, the system interprets their input using information like spell corrections, synonyms, and related concepts to form the retrieval query. This retrieval query is used to retrieve all potentially relevant keywords that are enabled to serve.

Step 2

Among the retrieved keywords, the system checks for eligibility based on keyword match type, and campaign and ad group criteria.

    1. For keyword eligibility, we use machine learning and natural language understanding technologies like BERT to better understand the intent behind search queries and match them to the most relevant, best-performing keywords. The system requires a much stricter match for exact keywords while allowing broader matching for phrase and broad match keywords.
    2. For campaign and ad group eligibility, we check the budget, geo-targeting, audience targeting, negative keywords, that the ad group has at least one approved creative and landing page, time of day restrictions, and more.
    3. If you’re using broad match, this is the step where broad match considers not only the current search term, but also the user’s location, their recent searches, your landing page, and other signals to understand what users are looking for as part of the retrieval process. This is how broad match can focus on searches that are more likely to perform well.


Step 3  

When deciding between multiple eligible keywords for the same account or set of linked accounts, the system prioritizes eligible keywords that are identical to the search term or the spell-corrected search term (across all match types).

In other words, if you use broad match keywords and want to ensure traffic goes to keywords that are identical to the user’s search term, you don’t need to repeat the same keywords in exact and phrase match.

Step 4

In each ad group that has an eligible keyword, the responsive search ads creative system automatically assembles the best-performing creative for the user.

With responsive search ads, candidate ads are automatically assembled from the available headlines and description lines. These candidate ads are evaluated for their relevance to the user’s query, and the creative expected to perform best is selected.

Step 5

Bids are then calculated for use with Ad Rank.

Ad Rank is a value that is used to determine where ads are shown on a page relative to other ads, and whether your ad will show at all. Your bids are part of the Ad Rank calculation. With Smart Bidding, a unique, optimal bid is set for each ad impression combination based on how likely it is that the ad, with the specific landing page, for the specific user search query and intent, will lead to a conversion. Note that Smart Bidding uses data from across your account to predict performance, and is not limited to data from a single keyword or campaign.

If you’re using manual bidding, the system will only use the static bid that was provided, along with any relevant bid modifiers.

Step 6

The system selects the best combination of relevance and Ad Rank among the ad candidates still in consideration. These candidates consist of a matched keyword or landing page, a creative, and a bid.

Relevance is determined by looking at the meaning of the search term, the meaning of all the keywords in the ad group, and the landing page within the ad group. If broad-match keywords are eligible to match, only relevant broad-match keywords from the most relevant ad groups will be selected. This is why it’s important to group your keywords into ad groups by theme. We consider these relevance signals in addition to Ad Rank when determining which keyword is selected.

Step 7

The ad with the highest Ad Rank from each advertiser then enters into the auction.

We then calculate and use Ad Rank to decide which final ad candidates will be selected among those with similar relevance. This includes phrase and exact match keywords that are eligible to match. Note that match type does not impact Ad Rank.

Note: This system eliminates the need to add the same keyword in multiple match types to funnel traffic to certain areas of your account. When you duplicate keywords in separate ad groups or campaigns, it can:

  •    Segment and reduce the available data that Smart Bidding can use for optimization, which may result in fewer conversions and higher costs.

  •   Increase the margin for error and make it harder to have consistent ads, budgets, targets, etc. across a large number of campaigns and keywords.

  •   Cause you to hit your Google Ads account limits.

If you have duplicate keywords for other reasons related to your business, you’ll want to check that your goals can still be accomplished before making any changes.

 Step 8

The auction then runs, and the ads with the highest Ad Rank across all advertisers show.


Reaching the right customers with your keywords

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How to find more queries that perform

World events, seasonality, and constantly changing search trends have shown us how dynamic search behavior can be. It is now impossible to capture every new opportunity with a manual approach. This is why many marketers now turn to solutions like broad match to reach search terms they expect, as well as those they haven’t discovered yet. That’s because broad match can reach searches related to your keyword, even if it doesn’t contain the exact same words. For example, a specific query like “most popular gifts this year” can now match with the broad match keyword gift ideas because we can tell they’re related in meaning, even though some words in the query and the keyword are different.

If you have clear performance goals and can accurately measure them within Google Ads, you’ll get the best performance by optimizing for those goals using Smart Bidding paired with broad match. This can help you get more conversions and conversion value within your performance goals because Smart Bidding ensures that you’re only competing in the right auctions, with the right bids, for the right users.

If you have other goals, like showing your ad 100% of the time when a user searches for your brand, you may want to consider Target Impression Share bidding paired with exact or phrase match.

The list below summarizes many of the important signals broad match takes into consideration.

Broad Match Signals



Other keywords in the ad group

System looks at other keywords in your ad group to better understand the meaning of a keyword

Keyword: pink socks Search term: salmon socks

Other keywords in ad group: red socks, blue socks, purple socks

The system understands “salmon” refers to the color of the socks, not socks with pictures of fish on them.

Previous searches

System looks at previous searches to better understand the intent of the current search

Keyword: chicago vs ny baseball Search term: chicago vs ny Previous searches: baseball scores

Based on the user’s previous searches,
the system understands that the user is interested in baseball scores between the two teams, even though the current search term only includes the two cities.

User location

System looks at the user’s location to find more relevant matches

Keyword: restaurants in NY Search term: Restaurants near me User location: New York

The system takes into account that the user is in New York in order to find more relevant matches.

Landing page

System looks at your landing page to better understand the context of your business

Keyword: shoes
Search term: RunFarFootwear 1000

Landing page content: shoes for running ultramarathons, including the RunFarFootwear 1000

The system looks at your landing page
to understand that you offer this type of shoe, so the search is relevant (even if your keyword doesn’t contain the specific words in the search).

Review the search terms report frequently to see which searches are triggering your ads and how those searches are performing. This report also helps you discover new ideas for creative and landing page content to align with what your customers are looking for. If you see terms that you don’t want to match to, you can add them as negative keywords. Keep in mind that negative keywords don’t look at the meaning of the keywords, only the words themselves. That means you’ll need to add synonyms, singular or plural versions, misspellings, and other variations if you want to exclude them.

You can also check consumer interest insights on the Insights page to understand the consumer intent behind these searches. These insights aggregate the top performing themes for the search queries that drove performance in your campaigns. You’ll see the number of people who searched for each theme, its growth and how it performed in your account.

When to use exact and phrase match

We still recommend exact and phrase match for specific use cases, such as:

  • Campaigns that don’t have conversion based goals and don’t use a conversion-based automated bid strategy, such as targeting an impression share on a specific set of search terms
  • Campaigns that may have specific budgets and goals for specific terms, like competitor campaigns
  • Campaigns where matching only to specific user searches is mandatory based on industry regulations–like those in finance, pharma, and other regulated industries

Setting the optimal bid for each user

Smart Bidding is a set of automated bidding strategies that use machine learning to optimize for conversions or conversion value. Smart Bidding sets precise bids for each and every auction to help drive higher conversion volume or conversion value for your budget, return on ad spend (ROAS), or cost per action (CPA) goals.

Why it’s critical to use Smart Bidding with broad match

Every search query is different, and bids for each query should reflect the unique contextual signals present at auction time. Smart Bidding takes into account signals like a user’s operating system, web browser, language settings, time of day, presence on a remarketing list, and many more to optimize for performance differences across platforms and users. Smart Bidding also uses data from across your account to predict performance and is not limited to data from a single keyword or campaign. This additional context allows Smart Bidding to more accurately predict the conversion likelihood of each auction and set the optimal bid.

Essentially, Smart Bidding ensures that, for all of the relevant searches you could reach with a broad match, you’re only competing in the right auctions, at the right bid, for the right user. If you are reporting and optimizing for conversion values, Smart Bidding not only helps you get more conversions within your goals, but those conversions are also more valuable. This is why it’s critical to measure and report on the conversion actions that matter most to your business.

For example, let’s say you manage an Italian restaurant in San Francisco. Broad match can help you find a variety of interested people—from a couple searching “places to eat tonight” on their phones nearby, to a family searching “family-friendly restaurants in SF”, to a traveler searching “best risotto in North Beach” on their laptop in their hotel. While any of these users could visit your restaurant, the optimal bid to reach them will vary. Manually adjusting the bid on individual keywords for each user is impossible, and would lead to missed conversions. Smart Bidding can use machine learning signals to understand these users and automatically bid more for those that are most likely to buy from you. Learn more about how Google’s automated bidding systems do this.

You can also use Google Ads data-driven attribution (DDA) modeling to understand the contribution of each keyword across the conversion path. DDA is fully integrated with Smart Bidding in Google Ads. If you use an automated bidding strategy to drive more conversions or conversion value, your bids will use this data to help you meet your goal.

How using Smart Bidding with broad match-only campaigns can help you simplify your accounts

When you add new keywords or move keywords to a different ad group, Google Ads bidding algorithms don’t have to relearn performance from scratch. To explain this, it’s important to understand the difference between query and keyword. A search query is the text that a user types into the search bar, which we also refer to as a user’s search. A keyword is a word or phrase that you choose to describe your product or service, which is used to show your ads to users that are searching.

Because our bidding algorithms learn at the query level rather than the keyword level, if a search query has already been matching to keywords in other parts of your campaigns, the algorithms simply apply what they’ve learned about it across your account to make more informed bidding decisions. In practical terms, this means you can simplify your accounts by predominantly using broad matches for performance-based keywords. That’s why if you’re using Smart Bidding, there is no performance benefit from repeating the same keyword in multiple match types in a campaign.

Advertisers that switch their exact match keywords to broad match in campaigns using a target CPA can see an average of 35% more conversions.
Google Search Marketing - Sem &Amp; Seo
Internal Data 2021
Advertisers that switch their exact match keywords to broad match in campaigns using a target ROAS can see an average of 20% more conversion value.
Google Search Marketing - Sem &Amp; Seo
Internal Data 2021

How broad match helps Smart Bidding perform better

Smart Bidding works best when it can optimize against your goals with as much flexibility as possible. To explain how, it’s important to understand the concept of marginal CPA3 and marginal ROAS4. Marginal CPA focuses on the cost of additional conversions, and marginal ROAS focuses on the additional value you get from additional spend.

  • When you have a shared budget and single portfolio bid strategy across all campaigns with the same goals, Smart Bidding can optimize towards the same marginal CPA or marginal ROAS across all related traffic.
    • You will get the best performance by keeping traffic together as it helps automation equalize the marginal ROI across all traffic, leading to the most possible volume at a given ROI level. That’s why we recommend using one campaign per business objective, and one ad group per creative theme. For example, if you have different conversion goals for emerging markets and core markets, they should be separated into different campaigns so Smart Bidding can optimize towards each of those goals.


  • The more you split up traffic, the more likely it is that you may restrict Smart Bidding from finding the most conversions at your target.
    • Smart Bidding would need to attain the target CPA in each segment separately, which can result in a higher marginal cost for some conversions, reducing the overall efficiency of the bid strategy. This is why we recommend consolidating into broad match keywords.

Here’s an example of how it could work in two scenarios using a target CPA of $10:

  • With consolidated traffic, e.g. using only broad match keywords in a campaign, or keeping all variants of the same keyword in the same campaign / sharing a portfolio bid strategy
    • When all broad match traffic for a keyword is consolidated, Smart Bidding can optimize to get you the best performance. For example, it might set a marginal CPA of $12.50 to attain the maximum possible conversion volume at your CPA target of $10.


  • With segmented traffic, e.g. separate campaigns that don’t share a portfolio strategy
    • When exact match or phrase match traffic for a keyword is in separate campaigns that don’t share a portfolio bid strategy, Smart Bidding will need to set two different marginal CPAs (i.e. $14 for exact and $11 for broad). This would result in less conversion volume at your CPA target of $10, because the lower marginal CPA of the broad match keyword means you’ll compete in fewer auctions. Additionally, when you use exact match, you may eventually become constrained by user search volume–meaning that incremental conversions could rise in cost.


CPA Target: $10


Separate campaigns that don’t share a portfolio bid strategy

Consolidated traffic


Running shoes – exact match

Running shoes – broad match

Running Shoes


[running shoes]

running shoes

running shoes

Marginal CPA when avg CPA = $10




Comparing the costs of exact match and broad match

There’s a common perception that you can get conversions at a lower cost by using exact match.

If you pause an exact match keyword and have a broad match keyword pick up that traffic with the same bid, creative, and budget, this will not change how the traffic that used to match to the exact match keyword is evaluated. All other factors being equal, the cost for that traffic is equivalent to the exact match keyword. Adding new traffic, or moving existing traffic from one keyword to another—while keeping everything

else constant—doesn’t change how that traffic is evaluated.
However, your reporting and account structure may make the exact match appear cheaper. For example:

  • You’re comparing cost per click (CPC) instead of CPA or ROAS
    • Using broad match with Smart Bidding is designed to be the most efficient way to get you the most
  • conversions within your bidding objective, not the cheapest CPC.
    You’re using broad match only to find new queries and exact match for your performance-based queries
    • Comparing broad match performance for new queries vs. exact match performance for queries you already know will perform, is not an apples-to-apples comparison. We recommend setting up a test on the Experiments page to compare the performance of the same keywords in the broad match and exact match.

Creating the most relevant ad

Responsive search ads combine your creativity with the power of machine learning to help you show more relevant ads to more people. They help you compete in a wider variety of relevant auctions by delivering ads that adapt to show the right message for the right query. This means that you can drive incremental conversions while creating fewer ads.

Why keyword theming is important for ad relevance

Creative assets and landing pages are shared across your ad group. Focusing each ad group on a creative theme makes it easier to write relevant, high-quality creative assets that perform well across all of the traffic in your ad group. That’s also why we recommending grouping your keywords into similar themes―to make it easier for Google to understand your keywords, select the best one, and determine which ad should serve for each query.

Ad Strength ― which gives you feedback to help you provide the right messages to your customers―can help you determine if the themes of your keywords are incorporated into your ad copy. Ad Strength has two components: the overall rating that indicates the effectiveness of a relevant ad, and the specific action item(s)
that can improve the ad. When making changes to your keywords, Ad Strength will update to reflect the relevance of your ads to those keywords. Learn more about how to create effective Search ads.

Grouping your keywords into similar themes makes it easier for Google to understand your keywords, select the best one, and determine which ad should serve for each query.
Google Search Marketing - Sem &Amp; Seo
Internal Data 2021

Why responsive search ads work well with broad match

Creative automation works with broad match because the system needs flexibility to optimize the right creative variant to each query. By entering multiple headlines and descriptions in a responsive search ad, Google Ads will automatically learn which combinations perform best across all of the traffic provided by broad match.

How match types affect Quality Score

Keep in mind that changing keyword match types will not impact Quality Score because it’s based on the historical impressions for searches that are identical to your keyword. For example, if all else is equal (bid, ad, etc.), the broad match keyword running shoes and exact match keyword [running shoes] should have the same Quality Score.

If your broad match keyword running shoes matches to the search “shoes for running”, that doesn’t factor into its Quality Score. Note that Quality Score is meant to be a diagnostic tool only, to give you a sense of how your ad quality compares to other advertisers.

Advertisers that switch from expanded text ads to responsive search ads, using the same assets, in campaigns that also use broad match and Smart Bidding, see an average of 20% more conversions at a similar cost per conversion.
Google Search Marketing - Sem &Amp; Seo
Internal Data 2021

Key Takeaways

The consumer journey and search behavior is constantly changing, which makes it impossible to anticipate every keyword that’s relevant to your business. Taking a manual approach to this challenge has only led to excess time being spent on managing accounts with a high margin of error. That’s why Google Ads keywords have been designed to work with our other automated products in an ecosystem—namely responsive search ads and Smart Bidding—to give you the best reach, relevance, and performance in any environment. Here are some final takeaways to keep in mind:

  • Align your keyword strategy with your bidding: You should group your campaigns by your bidding goals.
    If you can accurately measure your conversions and use a conversion-based Smart Bidding strategy, broad match gives you the most reach and conversions within your goals. If you have other bidding goals, like Target Impression Share, you may want to consider using phrase match or exact match.

  • It’s critical to use Smart Bidding with broad match: Broad match is the only match type that uses all of the signals available to understand the intent of both the query and your keyword, while having the flexibility to find the most relevant match that is expected to perform for you. Smart Bidding ensures that for all the relevant searches broad match helps you reach, you are competing in the right auctions, with the right bids aligned to your performance goals, for the right user.

  • Measurement is the foundation that allows Search automation to work. Make sure you’re measuring the conversions that matter to your business, and that you’re providing that data through Google so Smart Bidding can optimize for the right customers. Also use data-driven attribution to understand the contribution of each keyword across the conversion path.

  • Keyword theming is more important than ever: Grouping your keywords into ad groups and campaigns with similar themes makes it easier for Google to understand your keywords, select the best one, and determine which ad should serve for each query.

  • Search automation is designed to help you spend less time managing your ads, and more time managing your business: With the advances in automation and machine learning, we now recommend broad match as the main match type for your performance campaigns, combined with responsive search ads and Smart Bidding.

About the Author

Zabi Niazi - Director of Search Marketing SEM and SEO

Hands-on execution & Revenue-focused digital marketer with expertise in Design & Operations centered around people, processes & technology engineering a Demand-Gen Engine capable of delivering innovative experiences that tell the brand story and map to the buyer's journey generating awareness, acquisition, retention, and advocacy.