How many keywords should I use per ad group?

How many keywords should you use per ad group? (The numbers that actually work)

After managing Search and Display accounts for 15+ years, I can tell you the “right” number of keywords per ad group isn’t a magic constant—it’s a relevance threshold. The moment you can’t write a single set of ads (and send traffic to a single landing page) that honestly fits every keyword in that ad group, you’ve added too many.

That said, there are practical ranges that consistently produce better click-through rate, conversion rate, and ROI—because they keep your message, intent, and landing page tightly aligned.

Search campaigns (most common): typically 10–20 keywords, with 20–30 as an upper bound

For Search, a great starting point is 10–20 closely related keywords per ad group. If the theme is truly tight (same service/product, same intent, same landing page), you can often go up to 20–30 terms without losing focus.

Once you go past ~30, ad groups usually become “keyword buckets,” and performance tends to slip because your responsive search ad can’t stay specific, your landing page match gets weaker, and optimization decisions get muddy (you’re trying to fix multiple problems inside one ad group).

Also important: you rarely need to build massive keyword lists like it’s 2016. Broader match options can cover the reach of narrower match types, and close variants already pick up common meaning-equivalent searches (plural/singular, misspellings, stems, etc.). In plain English: you can often run fewer keywords and still capture the demand—while keeping the ad group cleaner.

Display keyword targeting: usually 5–20 keywords per ad group

For Display keyword targeting (contextual/content-based delivery), you generally want a smaller set: 5–20 keywords. Display keywords behave differently than Search keywords, so stuffing in lots of variations tends to broaden targeting in ways that reduce relevance and waste spend.

Smart campaigns: aim for 7–10 keyword themes

If you’re using Smart campaigns, think in terms of “keyword themes” rather than classic keywords. The practical best practice here is 7–10 keyword themes maximum. More than that often dilutes relevance and makes it harder for the system to learn what you really want.

Don’t confuse “limits” with “best practices”

Yes, the platform can technically handle far more than 30 keywords in an ad group (the system limits are very high). But high limits exist for edge cases and automation—not because it’s a good structure for performance. The goal is not “how many can I fit,” it’s “how tightly can I align intent, ad text, and landing page.”

A simple framework to decide your number (without overthinking it)

Rule #1: One ad group = one landing page promise

If the keywords in an ad group would ideally go to different pages (or require different pricing, different qualifiers, or different calls-to-action), split the ad group. This is the fastest way to improve ROI because it improves pre-click relevance (higher CTR) and post-click relevance (higher conversion rate).

Rule #2: Your responsive search ad should “naturally fit” every keyword

Responsive search ads perform best when you can write a strong set of headlines/descriptions that are truly on-theme. The platform also limits how many responsive search ads you can keep enabled per ad group, so you can’t “solve” messy keyword groupings by creating dozens of hyper-specific ads inside one ad group.

As a gut check: if you find yourself relying on keyword insertion to force relevance across a wide mix of terms, your ad group is probably too broad. Keyword insertion can be helpful, but it should be a polish tool—not a structural fix.

Rule #3: If you need different negatives, you need different ad groups

When keyword sets require different negative keyword strategies to stay clean, that’s a strong signal they don’t belong together. Mixing them usually creates a cycle of constant “search terms cleanup” without ever fully fixing the root issue.

Rule #4: Match type doesn’t justify extra keywords anymore

Many advertisers still build separate ad group keyword lists like: exact + phrase + broad for the same core term, multiplied by word order variations. In modern matching, this is usually redundant. Broader match options can capture the reach of narrower types, and very similar keywords are often effectively duplicates in how they match. The better play is typically fewer, cleaner keywords paired with clear ad groups, strong ads, and the right bidding strategy.

• If you’re using broad match, it’s generally most effective when paired with Smart Bidding and tight ad group themes.
• If you need strict control, use exact/phrase—but keep the theme tight rather than expanding the list endlessly.

When to use fewer vs. more keywords per ad group (practical scenarios)

Use fewer keywords (often 5–12) when ROI depends on precision

If you’re in a high CPC market (legal, SaaS, medical, home services in competitive metros) or you’re optimizing to a hard CPA/ROAS target, smaller ad groups usually win. You’re paying too much per click to allow loose relevance. Fewer keywords makes it easier to keep ads specific, control intent, and send users to the best-fitting page.

This is also the right move when you have clear intent splits like “emergency” vs. “scheduled,” “commercial” vs. “residential,” “buy” vs. “repair,” or “pricing” vs. “reviews.” Those should almost always be separate ad groups (and often separate campaigns if budgets and goals differ).

Use more keywords (up to ~20–30) when the intent is truly identical and volume is low

If search volume is limited and the terms are genuinely interchangeable (same buyer intent, same offer, same page), then combining into a 20–30 keyword ad group can be efficient. The key is that the ad group still reads like a single topic, not a category.

Split your ad group immediately if you see any of these symptoms

• Your top search terms look like multiple different “services” (not just variations) and require different messaging.
• You can’t write headlines that feel specific without awkward, generic language.
• One keyword/theme is getting most of the spend and the rest are “along for the ride,” making optimization slower and less clear.
• You’re constantly adding negatives to stop unrelated intents that keep coming back.

A clean, high-performing “default” you can implement today

If you want a simple standard operating procedure that works across most accounts: build ad groups around a single product/service theme, start with 10–20 keywords (cap at 30), and require that every keyword maps cleanly to the same landing page intent. Then scale by adding more ad groups—not by inflating keyword counts inside existing ones.

That structure keeps your ads more relevant, makes performance data easier to act on, and typically improves ROI faster than any “hack” involving massive keyword lists.

For most standard Search campaigns, a solid starting point is 10–20 closely related keywords per ad group, with an upper ceiling around 20–30 only if every term shares the same intent and can honestly use the same ad message and landing page; beyond that, ad groups often turn into broad “keyword buckets” that are hard to write good RSAs for and require constant negative-keyword clean-up. In precision-sensitive or high-CPC markets, you’ll usually want fewer (often 5–12) to keep messaging and landing pages highly specific, while low-volume niches can sometimes justify combining up to ~20–30 interchangeable synonyms. A practical rule to sanity-check your structure is “one ad group = one landing page promise”: if keywords need different messaging, different negatives, or a different page, split them. If you want help applying this in your own account, Blobr connects to Google Ads and uses specialized agents like Keyword Ideas Finder (to expand with relevant new terms without duplicates) and Keyword Landing Optimizer (to map keywords to the right landing pages and suggest when to split ad groups) so your structure stays tight as match types and search behavior evolve.