Broad match is the loosest of the keyword match types used in search advertising. A keyword set to broad match can enter the ad auction for any query the platform considers related to it, including searches that share none of its words. It exists because users phrase the same need in countless ways, and no advertiser can list them all.

On Google Ads, broad match is the default: a keyword typed without punctuation is broad. According to Google's help page, ads "may show on searches that are related to your keyword", which "can include searches that don't contain the direct meaning of your keywords". Microsoft Advertising uses the same convention. As of October 2026 both platforms still offer broad match keywords alongside phrase and exact match, although Google's campaign-wide broad match switch has been folded into AI Max for Search.

How broad match decides which searches qualify

The keyword itself carries the setting. "running shoes" with no quotation marks or brackets is broad; "running shoes" in quotes is phrase match, and [running shoes] in square brackets is exact match. The Google Ads API stores it as the enum BROAD. Word order does not matter: Google's help page notes that the broad keywords "red car" and "car red" are treated as duplicates.

What separates broad match from the other two types is the evidence it uses. According to Google, the system weighs three classes of signal when deciding whether a query is related: the user's recent search activity, the content of the landing pages and assets, and the other keywords in the same ad group. Google documentation published in August 2025 went further, describing broad match as the only match type that uses all available signals. Its example was a broad keyword "gift ideas" serving on "most popular presents this year".

Two Google software engineers, Dorothea Wiesmann Rothuizen and Wojtek Skut, wrote in March 2023 that broad match had become reliant on large language models trained on "billions of pieces of text". Older versions, they said, could link "treating a pet at home" to "treats for pets" but missed the relevance of "without a vet", because the phrases shared no words. The newer models also read word direction and can match a query in one language to an ad in another.

Matching is only half the decision. Once several keywords in an account qualify for one query, a prioritisation rule picks which enters the auction. As set out in PPC Land's keyword explainer, Google gives first place to an exact match keyword identical to the query, then treats phrase and broad keywords, including AI Max, as a single pool ranked by relevance, with Ad Rank breaking ties.

Why bidding and broad match are tied together

Google presents broad match and Smart Bidding, its automated auction-time bidding, as a pair. "It's critical to use Smart Bidding with broad match," the help page states, because "bids for each query should reflect the unique contextual signals present at auction-time." The logic is that a wide net catches queries of uneven value, and only a bid set per auction, using conversion predictions, can price them differently.

Google's performance claims rest on that pairing. Internal data from July 2021, cited in the August 2025 documentation, showed that switching exact match keywords to broad yielded 35% more conversions in target cost per acquisition (CPA) campaigns and 20% more conversion value in target return on ad spend (ROAS) campaigns. Those are Google's figures on Google's inventory. They have not been independently audited.

The platform has also nudged accounts toward the setting. In July 2024 broad match became the default for new Search campaigns when a Smart Bidding strategy is chosen, according to Search Engine Land, with Ginny Marvin, Google's Ads Product Liaison, clarifying the condition on July 11. On June 30, 2025, Google added single-campaign broad match experiments, splitting traffic inside one campaign between the existing keywords and a version with broad match added.

Origin and evolution

Broad match is as old as Google's keyword auction, and so is the argument about it. On October 3, 2003, ClickZ reported that Google was widening broad match for its roughly 150,000 advertisers so that a keyword such as "cashmere sweater" could show for "cashmere cardigan" or "cashmere turtleneck". The number of related matches would depend on a keyword's click-through rate (CTR), and broad and phrase keywords needed a CTR near 1%, against about 0.5% for exact. "We're trying to simplify the amount of work it takes to build keyword campaigns," Salar Kamangar, then Google's director of product management, said. Kevin Lee, chief executive of Did-it.com, said Google was "just trying to more effectively monetize the search tail."

The broad match modifier (BMM), launched in July 2010, required words marked with a plus sign to appear. Google folded it into phrase match in 2021. Microsoft instead began serving remaining BMM keywords as broad match from March 15, 2023, according to MediaPost.

The scope then moved from the keyword to the campaign. At the end of June 2023 Google introduced a campaign-level broad match setting, together with brand restrictions available only to campaigns that used it. Turning it on converted every phrase and exact keyword in the campaign to broad and forced new keywords to broad. It required conversion-based Smart Bidding. Switching it off restored the original match types, but keywords converted in the meantime appeared as removed and had to be reinstated, according to PPC Land's account of the migration. Microsoft's equivalent, Predictive Matching, likewise applied broad match to every keyword.

Absorption into AI Max

Google announced AI Max for Search campaigns on May 6, 2025. Its central component, search term matching, extends broad match logic to queries for which no keyword exists at all. On August 3, 2026, it blocked creation of new campaign-level broad match configurations in the interface, Google Ads Editor and every API version, then emailed advertisers on August 5.

Migration ran progressively from September 1 to September 30, 2026. Converted campaigns kept their brand lists and had search term matching switched on, but text customisation and final URL expansion off. The API field campaign.broad_match_migration_date_time records when each campaign moved, and the legacy entity disappears from all API versions around September 2027. Google's notice addressed the campaign setting, not individual broad match keywords.

Microsoft followed. It moved Predictive Matching into AI Max search term matching, reported on July 29, 2026 without an effective date, and made AI Max available to all accounts on August 19, 2026.

Why it matters for marketers

Broad match decides how much of an account's spend goes on queries the advertiser never chose. The trade is reach for predictability, with heavier reliance on conversion tracking, since Smart Bidding can only value what it measures.

Google's August 2025 guidance also discouraged duplicating keywords across match types, saying split data weakens Smart Bidding.

Limitations and disputes

The central dispute is whether broad match finds new demand or reprices existing demand. In December 2024 Navah Hopkins, then at Optmyzr, reported that switching campaigns to conversion-based bidding was turning the broad match campaign setting on without notice. Marvin said it was "not the expected behavior".

Independent figures cut against Google's. An analysis of more than 250 retail campaigns put AI Max ROAS about 35% below traditional match types, and one agency's tests across about 30,000 search terms found 99% of AI Max impressions produced no conversion. Microsoft's own data adds a wrinkle: across 44 AI Max experiments between June and August 2026, campaigns relying more on exact and phrase keywords showed higher uplift.

Controls are asymmetric. Positive broad match expands to meanings, but negative keywords match strings. According to Google, a negative broad keyword blocks a query only when all its words appear, in any order, and does not cover close variants. Reporting has thinned too: since May 2026 Google's search terms report shows, for some AI Mode and Lens queries, a "best approximation of the user's intent" rather than what was typed, which makes broad match drift harder to audit and to exclude.

Not the same as

Phrase match. Phrase match lets ads show on searches that include the keyword's meaning. Broad match only requires the search to be related.

Broad match modifier. BMM was a separate match type that required marked words to appear. It no longer exists on either platform; PPC Land's match type explainer covers its history.

AI Max search term matching. Broad match starts from a keyword. Search term matching can serve with no keyword involved, and Google reports it separately as the AI_MAX match type.

Amazon broad match. On Amazon Ads, broad match in Sponsored Products historically meant a search containing all of a keyword's words in any order. According to Perpetua, Amazon widened it to variations and synonyms in 2023, after doing so for Sponsored Brands in 2019.

Recent developments

On September 4, 2026, Marvin confirmed a small experiment letting exact and phrase keywords serve ads in AI Mode, until then reachable only through AI Max, Performance Max or broad match with Smart Bidding. Google also added brand inclusion and exclusion controls inside AI Max from late May 2026. Meanwhile Smarter Ecommerce found that nearly 29% of exact match impressions in its EMEA ecommerce sample had been broadened by AI Max by July 2026, suggesting that broad behaviour now reaches beyond broad keywords. As of October 2026, broad match keywords remain the default on both platforms.

Timeline

  • October 3, 2003: Google widens broad match to related searches, with CTR-based thresholds.
  • July 2010: Google launches the broad match modifier.
  • February 18, 2021: Google begins folding broad match modifier behaviour into phrase match.
  • July 2021: Google blocks creation of new BMM keywords; internal data later cited for broad match's 35% conversion claim.
  • March 2023: Google engineers describe large language model upgrades to broad match.
  • March 15, 2023: Microsoft Advertising begins serving BMM keywords as broad match.
  • Late June 2023: Google introduces the campaign-level broad match setting and brand restrictions.
  • 2023: Amazon extends Sponsored Products broad match to synonyms and variations.
  • July 2024: Broad match becomes the default for new Google Search campaigns using Smart Bidding.
  • December 26, 2024: Google investigates broad match being switched on during bidding changes.
  • May 6, 2025: Google announces AI Max for Search campaigns.
  • June 30, 2025: Google launches single-campaign broad match experiments.
  • August 2025: Google publishes expanded broad match documentation.
  • April 15, 2026: AI Max leaves beta; migration of legacy settings scheduled.
  • July 29, 2026: Microsoft's move of Predictive Matching into AI Max reported.
  • August 3, 2026: Google blocks new campaign-level broad match configurations.
  • August 19, 2026: Microsoft AI Max reaches all accounts globally.
  • September 1-30, 2026: Google migrates broad match setting campaigns to AI Max.
  • September 4, 2026: Google confirms test of exact and phrase keywords in AI Mode.
  • Around September 2027: Legacy broad match setting entities removed from remaining API versions.

Summary

Who. Google Ads and Microsoft Advertising define and operate broad match. Advertisers and agencies apply it keyword by keyword, while Smart Bidding and AI Max increasingly govern how far it reaches. Amazon Ads runs a separate, narrower version.

What. The default and loosest keyword match type, allowing an ad to compete on any query the platform judges related to a keyword, using signals such as recent searches, landing page content and the other keywords in the ad group.

When. Broad match dates from Google's early keyword auction and was widened in October 2003. Language model upgrades arrived around 2023, a campaign-wide setting launched in June 2023, and that setting migrated into AI Max between September 1 and 30, 2026.

Where. In Search campaigns on Google Ads and Microsoft Advertising, in their APIs as the BROAD match type, and in successor features such as AI Max search term matching.

Why. It lets advertisers reach queries they could never list, at the cost of control and visibility. Platforms say it drives more conversions when paired with automated bidding; independent tests and advertisers dispute how much of that volume is new and how much is waste.