RSA Headline & Description Tester

What it does

The RSA Tester builds and validates a Google Responsive Search Ad outside Google Ads, so you can preview, character-check, and review for repetition before pasting into your campaign. Up to 15 headlines (30 character limit each), up to 4 descriptions (90 character limit), with character counters per asset, repetition warnings between similar headlines, an ad-strength estimate, and rendered desktop and mobile previews showing what the ad will look like in search results.

Common situations

You’re launching a new campaign and need to assemble RSA assets that all fit Google’s character limits. The tester catches over-length entries before Google rejects them and shows the assembled preview — much faster than typing in Google Ads, hitting save, getting an error, fixing it, and saving again.

You’ve been told your existing RSAs have “Poor” ad strength in Google Ads but you can’t see why. The tester’s repetition warnings and asset count checks reveal what’s missing — usually too few unique headlines, or several headlines that share most of their tokens.

You’re handing RSA copy to a client for approval and want to show them what the ad will look like rather than just a list of headlines and descriptions. The desktop and mobile previews are the closest static representation possible to the live SERP rendering.

You’re testing a new ad message and want to understand which headline pairings will appear most often. With three headlines visible per impression and Google rotating combinations, the tester helps you spot which combinations would read awkwardly together — often a reason to pin a specific headline to position 1.

You’re rewriting an existing campaign’s ads and need to ensure the new copy has enough variety. RSAs with 15 headlines outperform those with 5; the tester shows you progress against the 15-headline target plus warns when several headlines are too similar.

What you need to know

Responsive Search Ads (RSAs) are Google’s current default ad format for the Search Network — they replaced Expanded Text Ads (ETAs) in mid-2022. The format gives you up to 15 headlines and 4 descriptions; Google’s auction system picks combinations of three headlines and two descriptions per impression, learning over time which combinations perform best for which queries.

The format limits, rules, and best practices:

Headlines: 30 character limit each, up to 15 maximum. The minimum is 3, but ad strength suffers below ~8. Headlines should each communicate a different angle — features, benefits, social proof, brand, urgency, CTA — to give Google variety to test. Three headlines are shown per impression; the order is variable unless you pin.

Descriptions: 90 character limit each, up to 4 maximum. Two are shown per impression. Descriptions should support and expand on the headlines without repeating them.

Display paths: two optional path fields (15 characters each) that appear in the URL display next to the domain. They don’t have to match the actual URL path; they’re cosmetic. Use them to add context the URL alone doesn’t.

Pinning: you can lock a specific asset to position 1, 2, or 3 (for headlines) or 1, 2 (for descriptions). Pinning is useful for legal/compliance text that must appear in a specific position, or for guaranteeing a brand mention. Over-pinning hurts ad strength because it removes Google’s ability to test combinations — pin sparingly, ideally only for compliance.

Ad strength is Google’s UI label for the variety/coverage of your asset set. “Excellent” requires roughly: 13+ headlines, 4 descriptions, no excessive pinning, and headlines covering distinct themes. “Poor” usually means under 5 unique headlines or heavy repetition. Excellent ad strength doesn’t directly improve auction position, but it increases the variety Google can test, which usually correlates with better long-run performance.

Common rejection reasons the tester flags: over-length characters, missing required minimums (under 3 headlines or 2 descriptions), repeated punctuation (!!!, ???), ALL CAPS over 4 characters, generic CTAs (“click here”), unverifiable superlatives (“#1”, “best”). The Ad Copy Compliance Checker goes deeper on the policy side.

The tester’s previews use Arial-equivalent metrics to approximate Google’s actual SERP rendering. Real Google rendering varies slightly with browser, screen size, and SERP layout, but the previews here match within a few pixels — enough to spot truncation before launch.

Frequently asked questions

What’s a Responsive Search Ad?

Google Ads’ default ad format for the Search Network since June 2022. You provide up to 15 headlines and 4 descriptions; Google’s system picks which combinations to show in real time, optimising for performance per query. Replaced the older Expanded Text Ad (ETA) format.

How many headlines and descriptions do I need?

Minimum is 3 headlines and 2 descriptions. Practical recommendation is all 15 headlines and all 4 descriptions — ad strength scales with the variety you provide, and Google’s testing benefits from more options.

What does “ad strength” actually measure?

The variety, length, and uniqueness of your asset set. Excellent requires: 13+ headlines, 4 descriptions, headlines covering distinct themes (features, benefits, brand, etc.), and minimal pinning. Poor usually means too few unique assets or excessive repetition. Ad strength is informational — it doesn’t directly affect bid or position, but correlates with the system’s ability to optimise.

Should I pin headlines?

Sparingly. Pinning is useful for compliance (“Authorised dealer”, legal disclosures) or guaranteed brand mentions. Over-pinning (especially pinning multiple headlines to the same position) reduces Google’s ability to test combinations and lowers ad strength.

What’s the difference between headlines and descriptions?

Headlines are short benefit/feature/CTA statements (30 char limit) shown prominently. Descriptions are longer supporting copy (90 char limit) that expand on the headlines. Three headlines and two descriptions appear per impression.

Do display paths affect what URL the user lands on?

No — display paths are cosmetic and only affect what’s shown in the SERP. The actual URL the click goes to is the Final URL field in Google Ads.

Why is one combination of headlines showing more often than the others?

Google’s system optimises for performance over time. Combinations that drive higher CTR or conversion get more impressions; underperformers get fewer. After a few hundred impressions, you’ll see a winner emerge. This is also why providing 15 headlines matters — more variety gives Google more to test.

Can I see which combinations performed best?

Yes — Google Ads’ “Combinations” report (under the ad’s detail view) shows which assembled ads got impressions. Use this data to identify your strongest creative themes for future ad iteration.

Common problems

Problem: Ad strength stuck at “Average” despite 15 headlines.

The headlines probably overlap heavily. The tester flags pairs with >70% token overlap; spread your headlines across more themes — features, benefits, social proof, urgency, brand, CTA. Repeating “Free Shipping” in 4 different headlines counts as 1 unique signal.

Problem: Headlines pass character count in the tester but Google Ads rejects them.

Google Ads sometimes counts double-byte characters (em-dashes, smart quotes, emojis) as 2 characters. The tester counts UTF-8 character length; Google occasionally counts display width. If a headline is right at 30, swap em-dashes for hyphens and check again.

Problem: RSA was approved but ad strength dropped after a Google Ads update.

Google updates the ad strength algorithm periodically. A previously “Excellent” RSA might drop to “Good” after an update if the algorithm now expects more variety in a particular dimension. This is normal; review the suggestions in the Ads UI and add headlines covering missing themes.

Problem: Description appears truncated even though it’s under 90 characters.

90 characters is the upload limit; the actual display limit varies by SERP layout, viewport, and whether the ad has extensions. Mobile usually shows the first ~70 characters of the description; descriptions optimised for mobile are written to make the point in the first 60-70 characters.

Problem: Pinning a headline to position 1 caused ad strength to drop to “Poor”.

Over-pinning is the most common ad strength killer. If you’ve pinned two or more headlines to the same position, or pinned more than 3-4 headlines total, the variety the system can test collapses. Unpin everything except genuinely required positions; ad strength recovers within a recalculation cycle.

Tips

• Aim for the full 15 headlines and 4 descriptions every time. Ad strength doesn’t max out below that, and Google’s testing improves with more variety.
• Cover distinct themes per headline — feature, benefit, social proof, brand, CTA, urgency, USP. The tester’s repetition warnings catch headlines that lean on the same theme.
• Write the first 30 characters of each description as if it’ll be the only thing shown. On mobile and reduced-size SERPs, the second half often truncates.
• Pin only when you must. Compliance text and legally-required disclaimers are valid reasons; “I want my best headline first” is not.
• After uploading to Google Ads, check the “Combinations” report after a few hundred impressions. The combinations Google chose to show most are your strongest creative; let them inform the next iteration.

Related tools in this suite

The Ad Copy Compliance Checker is the policy-side companion — once the tester confirms your assets fit the format, the compliance checker flags the language patterns that cause auto-disapproval. The Quality Score Estimator is the next step for understanding how the assembled ad will perform in the auction.

What this looks like at scale

For a single campaign, the tester is the right tool. For an account with hundreds of ad groups, RSA assembly should be templated — repeated brand and CTA headlines that just-work across ad groups, with the per-ad-group variation in product/keyword headlines. That kind of structured creative work is part of how a paid search engagement typically operates after the toolkit-and-DIY phase.

Take it further

If you’ve been running RSAs for a while and want a structured review of which themes are working across your account, that’s the kind of work that benefits from real account access rather than per-ad-group spot checks. Talk through what’s there and we can scope a review.