How Many Keywords per Ad Group? What Google Actually Says

Google does not publish a fixed number for how many keywords per ad group a Search campaign should have. The working answer is to keep only the keywords that share one search intent and can be answered by the same ads and the same landing page; for most Search ad groups that is a short, tightly themed list, and with broad match and Smart Bidding it is often shorter than advertisers expect.

The only numeric guidance Google gives sits in its Display Network help, where it suggests a set of 5 to 20 keywords that relate to the ads in the ad group. That figure is about contextual targeting on websites, not about search queries, so it should not be copied into Search campaigns as a rule. The rest of this guide explains what decides the right size instead, how to spot an ad group that has grown too large, and how to fix it without breaking the account's learning.

Is adding too many keywords bad for Google Ads?

Adding many keywords is not bad in itself. Google allows up to 20,000 targeting items in a single ad group and 5 million per account, so the platform is clearly not trying to stop large lists. The problem appears when the keywords in one ad group stop meaning the same thing.

An ad group has one set of ads and usually one landing page. Every keyword in it borrows those ads. If the list mixes "emergency plumber", "plumbing course" and "how to fix a leaking tap", the same responsive search ad has to answer a person with a flooded kitchen, a person who wants a career change and a person who wants a free tutorial. Only one of those is likely to buy the service. The ad either becomes generic enough to fit all three, which weakens it for the buyer, or it stays specific and becomes irrelevant to the other two.

That mismatch shows up in three places. Ad Relevance, one of the three Quality Score components alongside expected click-through rate and landing page experience, drops for keywords the ad does not speak to. Click-through rate falls because the headline does not reflect the search. And reporting becomes harder to act on, because spend and conversions for unrelated intents are blended into one row.

So the question is less "how many" and more "how many different meanings". Thirty keywords that are all ways of saying the same thing can live together. Five keywords with three different intents should not.

How many keywords Google recommends per ad group today

For Search campaigns, Google's help content gives direction rather than a count. Its keyword guidance tells advertisers to group keywords and ads into ad groups based on products, services or other categories, and warns against putting all keywords and ads into one ad group. It also says you do not have to add every variant of every keyword, because all match types can capture related traffic.

The number Google does state, 5 to 20 keywords, comes from its article on choosing keywords for Display Network campaigns. On Display, keywords describe the theme of pages where the ad can appear, and a compact list of two- or three-word phrases tends to describe a theme clearly. That logic does not transfer neatly to Search, where each keyword is matched against what a person typed.

Two hard limits are worth knowing because they shape how an ad group is built: an ad group can hold up to 20,000 targeting items, and it can have up to 3 enabled responsive search ads. The second limit matters more in practice. Three ads are not enough to speak convincingly to a dozen different intents, which is another reason to keep each ad group to one theme.

Why the old SKAG approach faded

Single keyword ad groups, usually shortened to SKAGs, put one keyword (often in several match types) into its own ad group with ads written for that exact term. The method made sense when exact match meant the literal query and nothing else. Each ad group mirrored one search, so the headline could repeat the query word for word.

Two changes removed most of that advantage. First, close variants became part of every match type and cannot be switched off. Exact match now covers searches with the same meaning or intent as the keyword, which can include misspellings, plurals, reordered words and synonyms. A SKAG built around one phrase now collects many phrasings, so the one-query-one-ad precision it promised no longer exists.

Second, Google changed how it chooses between ad groups. When several keywords in an account could match a search, an exact match keyword identical to the search term is preferred first. If none is identical, Google uses AI-based relevance to limit matching to the most relevant ad groups, looking at the search term's meaning, all the keywords in the ad group and its landing pages. If candidates still tie, the one with the highest Ad Rank wins. In other words, the system now reads the whole ad group as a theme. Splitting one theme across twenty tiny ad groups gives it less context, not more.

SKAG structures also spread data thinly. Smart Bidding learns from conversions, and an account with hundreds of ad groups that each get a handful of clicks per month gives each ad group very little to learn from. The structure that once gave control now mostly adds management work.

How match types and Smart Bidding change the answer

Match type changes how much work each keyword does. A broad match keyword can reach searches related to its meaning, so one broad keyword may cover what used to take ten exact keywords. Phrase match sits between the two. Exact match is the narrowest, but as noted above it still covers close variants.

Google's own guidance pairs broad match with Smart Bidding and says Smart Bidding works best with broad match, because the wider set of searches gives the bidding model more to learn from and lets it set a bid for each auction from signals such as device, location and time. The practical result is that a well-structured broad match ad group with Smart Bidding might carry only a few keywords that define the theme, while the search terms report and negative keywords do the work of trimming irrelevant traffic.

Manual bidding pushes the other way. If you set bids yourself, you need keywords split so that terms with different values can carry different bids. That tends to mean more exact and phrase keywords and a longer, more deliberate list. Neither approach has a target count. The difference is where the control sits: in the keyword list for manual bidding, in the bid strategy and negatives for Smart Bidding.

One caution: negative keywords do not match close variants. If an ad group relies on a short broad list and negatives to stay clean, the negative list has to include the plurals and misspellings you want to block, because Google will not extend negatives to them automatically.

Signs an ad group has too many keywords

Look for these signals in the account rather than counting rows:

• Mixed intent in the search terms report. If one ad group's search terms include buyers, researchers and job seekers, the keyword list covers more than one intent.
• Low or "below average" Ad Relevance on a group of keywords that the ad copy does not mention. This is the most direct sign that the ad does not fit those terms.
• One responsive search ad serving unrelated searches. When the same headline combination appears for "price" queries and "how to" queries, the ad cannot be specific to either.
• A landing page that answers only part of the list. If half the keywords would be better served by a different page, they belong in a different ad group.
• A few keywords taking almost all the spend while dozens get no impressions. The quiet keywords add nothing and make the list harder to review.
• Keywords from the same ad group competing in other ad groups. If the same search terms appear across several ad groups, the themes overlap and the structure needs tidying.

How to split or consolidate ad groups

Splitting and merging follow the same rule: one ad group per intent that needs its own message or its own page. A practical sequence:

1. Export the search terms report for a period long enough to show real patterns, then label each term by intent (buy, compare, learn, local, brand).
2. Group keywords by those labels, not by wording. "Cheap dentist Bangkok" and "affordable dental clinic Bangkok" belong together; "dentist Bangkok" and "dental school Bangkok" do not.
3. Split when a group of keywords needs a different headline, offer or landing page. Create the new ad group with ads written for that intent, move the keywords, and add the moved terms as negatives in the old ad group only if traffic keeps leaking back.
4. Merge when several ad groups share one intent, one landing page and similar ads. Consolidating gives Smart Bidding more conversions per ad group and makes reporting clearer.
5. Pause rather than delete the old structure for a while, so its history remains visible if you need to compare.
6. Expect a period of adjustment. Moving keywords between ad groups changes where history sits, and automated bid strategies may need time to settle, so judge results over weeks rather than days.

How low-volume keywords affect an ad group

Google marks keywords with very little or no search history as "Low search volume". Such a keyword is inactive until search traffic for it increases, and Google re-checks the status regularly. Google states that these keywords do not hurt the account, and changing bids, Quality Score or ads will not change the status.

So the honest answer is that low-volume keywords do not damage performance directly. Their cost is indirect. They make the list longer and harder to audit, they hide which keywords actually drive results, and they count toward account limits. Google's suggested options include removing the keyword and finding alternatives in Keyword Planner, or using a broader match type that can reach related searches. In a broad match ad group, many long-tail exact keywords that sit at "Low search volume" can usually be removed with no loss, because the broad keyword already reaches those searches if they ever happen.

Keyword list approaches compared

What this means for advertisers in Thailand

Search behaviour in Thailand adds a few wrinkles. People often mix Thai and English in one query, such as a Thai word for "repair" with an English brand name, and loanwords can be spelled several ways in Thai script. Thai is also written without spaces between words, so the same phrase may be typed with or without a space.

Before adding every spelling as a separate keyword, check the search terms report to see which variants Google already maps to your existing keywords. Add a variant only when it is missing from the report and clearly matters. Keep Thai-language and English-language ads in separate ad groups when the landing pages differ by language.

FAQ: keywords per ad group

How many keywords should an ad group have?

There is no fixed number for Search; an ad group should hold only the keywords that share one intent and fit the same ads and landing page. That might be three broad keywords or thirty exact variants, depending on match types and bidding.

Does Google recommend 5 to 20 keywords per ad group?

Google gives the 5 to 20 range only in its Display Network guidance, not as a Search campaign rule. For Search it advises grouping keywords by product, service or category and says you do not need to add every variant.

Are single keyword ad groups still worth using?

For most accounts they are no longer worth the overhead, because close variants and AI-based ad group selection removed the precision they were built for. They can still make sense for a handful of very high-value terms that need their own ad copy and landing page.

Should I delete keywords with low search volume?

You can, and in broad match ad groups it is usually safe to remove them, but Google says they do not hurt the account. Removing them mainly makes the list easier to manage and audit.

If your ad groups have grown into long, mixed lists and you want them rebuilt around intent, see how our Google Ads management service structures accounts, or read about our Relevant Search approach to Google Ads. When the fix needs a page per intent, our landing page design team can build pages that match each ad group.