Responsive Search Ads: How to Write Headlines That Convert

Responsive search ads are now the default ad format in Google Ads. Expanded text ads were retired in 2022, and every search campaign you run relies on RSAs to deliver your message. The format gives Google up to 15 headlines and 4 descriptions to mix and match, testing different combinations to find what works best for each query and user.

The problem is that most advertisers treat RSAs like a form to fill in rather than a strategic asset to optimise. They write a handful of generic headlines, ignore the description fields, and move on. The result is ads that look like every other competitor in the auction.

An Optmyzr analysis of 1.1 million RSA campaigns found that RSAs deliver a 14.6% conversion advantage over the legacy expanded text ad format. But that advantage only materialises when the ads are built well. Poorly constructed RSAs with thin headline variety and no strategic intent will underperform, and the algorithm will have nothing meaningful to optimise.

This guide covers how to write RSA headlines and descriptions that actually convert, when and how to pin, and how to use ad strength signals without letting them override your judgement.

How Responsive Search Ads Actually Work

Understanding the mechanics helps you write better assets. When your RSA serves an impression, Google selects up to 3 headlines and 2 descriptions from your asset pool. The combination shown varies based on the search query, the user's device, their location, and other contextual signals.

Google's machine learning tests different combinations over time and learns which pairings drive the best performance. The more distinct, high-quality assets you provide, the more combinations Google can test, and the more likely it is to find a combination that resonates with each individual searcher.

This is why generic, repetitive headlines hurt performance. If five of your headlines say roughly the same thing, Google does not have five options. It has one, repeated five ways.

Writing Headlines That Work

Headlines do the heavy lifting in any search ad. They are the first thing users read, and in many cases the only thing they read before deciding to click or scroll past. With RSAs, you have room for up to 15 headlines of 30 characters each. You do not need all 15, but aim for at least 10 to 12 to give Google enough variety to optimise.

The Headline Categories Framework

Rather than brainstorming headlines randomly, work through these categories to ensure variety:

1. Keyword headlines (2 to 3): Include your primary keyword or close variations. These drive relevance signals and Quality Score. Example: "Enterprise CRM Software" or "CRM for Sales Teams".
2. Benefit headlines (2 to 3): Focus on what the customer gains. Not features, but outcomes. Example: "Close Deals 40% Faster" or "Reduce Manual Data Entry".
3. Social proof headlines (1 to 2): Leverage trust signals. Example: "Trusted by 5,000+ Teams" or "G2 Leader, 4 Years Running".
4. Urgency or offer headlines (1 to 2): If you have a genuine offer, use it. Example: "Free 14-Day Trial" or "No Setup Fees".
5. Differentiator headlines (1 to 2): What makes you different from the other ads on the page? Example: "No Long-Term Contracts" or "Australian-Based Support".
6. Action headlines (1 to 2): Direct calls to action. Example: "Get a Free Quote Today" or "See a Live Demo".

Headlines That Underperform

Avoid these common mistakes:

• Vague claims: "Best Service" and "Top Quality" are meaningless in a competitive auction. Every ad says this. Be specific.
• Redundant headlines: If three of your headlines all mention "affordable pricing," you are wasting asset slots that could test different angles.
• Headlines that do not stand alone: Each headline may appear in any position, or not at all. A headline like "And Much More" makes no sense on its own.
• Exceeding character limits: Headlines are capped at 30 characters. Write tight. Every character counts.

Writing Descriptions That Support the Headlines

Descriptions get less attention than headlines, both from users and from advertisers. But they serve an important role: providing the detail and context that headlines cannot. You get up to 4 descriptions of 90 characters each.

What Descriptions Should Cover

• Expand on benefits: Headlines are compressed. Descriptions give you room to explain why a benefit matters.
• Address objections: Common concerns about pricing, commitment, complexity, or trust can be addressed briefly in descriptions.
• Include a call to action: At least one description should tell the user what to do next: request a demo, get a quote, start a trial.
• Add specifics: Numbers, timeframes, and concrete details perform better than generalities. "Setup in Under 10 Minutes" beats "Quick Setup".

Description Variety

As with headlines, variety matters. Write descriptions that cover different angles. If one description focuses on pricing, another should focus on features, and a third on social proof or process. Google will test combinations of your headlines and descriptions together, and having diverse descriptions increases the chance of finding a strong pairing.

Pinning: When to Use It and When to Leave It Alone

Pinning allows you to lock a specific headline or description to a specific position. For example, you can pin a headline to Position 1 so it always appears first. This gives you control over your message, but it comes with a trade-off: it limits the combinations Google can test.

The Cost of Pinning

Google's own data indicates that pinning a single headline can cut testing potential by up to 75%. If you pin headlines to all three positions, you have essentially recreated a static expanded text ad and eliminated the adaptive advantage that makes RSAs effective.

That said, some level of pinning is often necessary and even beneficial. The key is to pin strategically rather than defensively.

When Pinning Makes Sense

• Legal or compliance requirements: If a disclaimer, licence number, or regulatory statement must appear in every ad, pin it to a description position.
• Brand name visibility: If your brand name must appear in every ad impression, pin a brand headline to Position 1.
• Core value proposition: If there is one message that must always be present (such as a limited-time offer), pin it to Position 1 or 2.
• Testing specific combinations: Temporarily pin headlines to test a specific messaging hypothesis, then unpin and let the algorithm optimise.

The Multi-Pin Technique

Instead of pinning one headline to Position 1, pin two or three headlines to Position 1. This guarantees that one of those headlines will always appear first, while still giving Google flexibility to choose between them. You maintain message control without reducing testing potential to zero.

For example, pin both "Enterprise CRM Software" and "CRM Built for Sales Teams" to Position 1. Google will always show one of these as the first headline, but can still vary the remaining positions freely.

Ad Strength: A Useful Signal, Not a KPI

Google's Ad Strength indicator rates your RSA from "Poor" to "Excellent" based on factors like headline variety, keyword inclusion, description uniqueness, and asset count. Google reports that advertisers who improve Ad Strength from "Poor" to "Excellent" see an average 15% increase in clicks and conversions.

That statistic is compelling, but it needs context. Ad Strength is a measure of best-practice compliance, not a direct predictor of your specific campaign's performance. An "Excellent" Ad Strength score means your ad has a lot of asset variety. It does not guarantee that those assets are well-written or that the messaging resonates with your audience.

How to Use Ad Strength Effectively

• Treat it as a floor, not a ceiling: Aim for "Good" or "Excellent" as a baseline, but do not sacrifice message quality to hit the score. A tightly focused "Good" ad that converts well is better than an "Excellent" ad stuffed with filler headlines.
• Use it to catch gaps: If your Ad Strength is "Poor," check for common issues: too few headlines, missing keywords, or repetitive descriptions. These are genuinely worth fixing.
• Ignore it when it conflicts with strategy: If pinning a headline for compliance drops your Ad Strength from "Excellent" to "Good," pin it anyway. Compliance matters more than a score.
• Focus on asset labels instead: Google labels individual assets as "Best," "Good," or "Low" based on actual performance data. These labels are more actionable than the overall Ad Strength score. Replace "Low" performing assets and create variations of "Best" performing ones.

An RSA Testing Framework

RSAs test combinations internally, but you still need to test at the ad level. Google recommends having at least three RSAs per ad group. Performance data supports this: advertisers with one RSA who add a second see a 6.6% increase in conversions on average, and adding a third RSA delivers a further 3.7% lift.

What to Test Across RSAs

Each RSA within an ad group should take a distinct messaging approach:

• RSA 1: Lead with benefits and outcomes.
• RSA 2: Lead with social proof and credibility.
• RSA 3: Lead with offers, pricing, or urgency.

Within each RSA, follow the headline categories framework above. The variation between RSAs should be in the overall messaging angle, not just individual headline wording.

Review Cadence

Check asset performance labels every two to four weeks. Replace assets labelled "Low" and add new variations to test. Do not make changes too frequently, as Google needs time to test combinations and accumulate statistically significant data. For most accounts, a monthly review cadence is appropriate.

Writing for Different Campaign Types

Brand Campaigns

Brand RSAs should reinforce your positioning and defend against competitors bidding on your name. Include your brand name in at least two headlines, and use descriptions to highlight differentiators that competitors cannot claim. Pinning your brand name to Position 1 is usually appropriate here.

Non-Brand Campaigns

Non-brand RSAs need to work harder. The searcher does not know you yet, so your headlines must combine relevance (keyword alignment) with differentiation (why choose you). Lean on benefit and differentiator headlines more heavily than brand headlines.

Competitor Campaigns

If you bid on competitor brand terms, your RSAs must offer a clear reason to consider an alternative. Generic headlines like "Try Our Software" will not cut it. Be specific about what you offer that the competitor does not. Comparison headlines work well here: "No Per-Seat Pricing" or "Switch in Under an Hour".

Headlines Are Strategy, Not Copywriting

The shift from expanded text ads to RSAs changed the advertiser's job. You are no longer writing finished ads. You are providing a pool of strategic assets that an algorithm assembles in real time. The quality of those assets, their variety, their specificity, and their strategic intent, determines whether the algorithm has good raw material or mediocre options.

Write headlines with clear categories. Test descriptions with distinct angles. Pin only when you have a genuine reason. Use Ad Strength as a guide, not a goal. Review asset labels regularly and replace what is not working.

If you want help building a paid search ad strategy that gets more from your RSAs, or need a fresh perspective on ad copy that has gone stale, reach out. We write and optimise RSAs across industries and can bring tested frameworks to your account.