Google Ads Ad Copy: How to Write Headlines That Convert

RSA vs. ETA: Why the History Still Matters

Google sunsetted Expanded Text Ads (ETAs) in June 2022, ending the ability to create new ETAs and replacing them entirely with Responsive Search Ads. But if you are auditing an account that ran ads before mid-2022, you will still encounter ETA data — and understanding the differences explains a lot about legacy performance benchmarks.

ETAs had a fixed structure: three headline slots (each 30 characters), two description lines (each 90 characters), and two paths. Advertisers controlled every combination, which made A/B testing predictable but slow. You ran two separate ads, waited for statistical significance, and paused the loser.

RSAs changed the game entirely. You now write up to 15 headlines and 4 descriptions. Google's machine learning tests thousands of combinations automatically, identifying which headlines appear together most often in high-performing combinations. The tradeoff: you give up deterministic control in exchange for scale and speed of learning.

The practical implication for anyone migrating from ETA data: your historical CTRs from ETAs are not directly comparable to RSA CTRs. ETAs typically showed lower click-through rates because they could not adapt copy to query context. RSAs, when written well, consistently outperform ETAs in CTR and conversion rate — but only if you fill all 15 headline slots with genuinely diverse options.

Headline Character Limits and Best Practices

Each headline is limited to 30 characters. That is less than a tweet, less than most short text messages — and it is where most advertisers waste the majority of their budget. Thirty characters sounds tight until you realize Google typically shows 3 headlines together in a single ad, giving you 90 combined characters to make your case. The key is writing headlines that work both alone and in combination.

Diversify by message type. A well-built RSA has headlines across five categories: keyword-matched headlines (2-3 that include your primary search term), benefit headlines (what the user gets), proof headlines (awards, years in business, reviews), urgency headlines (limited offer, available now), and CTA headlines (Get a Quote, Call Today). Google will mix and match these — and the combination of a keyword headline + proof headline + CTA headline is consistently one of the highest-performing patterns.

Avoid repetition across headlines. Google will not show two headlines with nearly identical phrasing in the same ad. If three of your fifteen headlines are variations of "Best Plumbers in Dallas," you have wasted two slots. Every headline should introduce a new idea or angle.

Front-load your value proposition. Since headlines can appear in any position, each one should be able to stand alone. Do not write a headline that only makes sense when paired with another specific headline. Treat every headline as a standalone statement.

Description Line Strategy

Descriptions give you 90 characters each across 4 available slots, and Google typically shows 2 at a time. Most advertisers treat descriptions as an afterthought — a place to dump the company tagline. This is a significant mistake. Descriptions are where you handle objections, build trust, and bridge the gap between a clicked headline and a completed form.

Structure descriptions like mini ad copy. Lead with a benefit or specific claim, then follow with a supporting detail or proof point. Example: "Licensed electricians available 7 days a week. Upfront pricing, no surprise fees, free estimates on all jobs." That 89-character description handles availability, pricing anxiety, and commitment threshold in a single read.

Include a soft CTA in at least one description. Even when Google shows your CTA headline, reinforcing the action in a description ("Call now or request a callback — same-day response guaranteed") gives hesitant searchers an extra push.

Use descriptions to differentiate from competitors. Search for your top keywords and read the existing ads. What are competitors saying? Write descriptions that say something different and more specific. "15-point inspection on every HVAC service call" beats "Quality Service You Can Trust" every time because it is concrete and verifiable.

Do not waste descriptions on brand names alone. If your brand is not yet recognized, leading with it in every description wastes the slot. Earn the click first; reinforce the brand on the landing page.

Headline Pinning — When and Why

Pinning lets you force a specific headline to always appear in position 1, 2, or 3. It sounds like a useful control mechanism, and in certain scenarios it is. But overuse of pinning is one of the fastest ways to tank your RSA performance — and it is more common than you would expect.

The problem with aggressive pinning: When you pin a headline to position 1, Google can only show that one headline in that slot. You remove the ability for the algorithm to find a better-performing combination. Google's own data shows that unpinned RSAs with 15 high-quality headlines get up to 10% more conversions than heavily pinned RSAs, at a similar cost per conversion.

When pinning is appropriate: Legal disclaimers that must appear in every ad. Brand name requirements from a franchisor. Compliance language in regulated industries like healthcare, finance, or legal services. Promotional deadlines ("Offer Ends Dec 31") where the specificity of the message overrides optimization value. Geographic qualifiers where a local ad absolutely must show the city name.

The right way to pin: If you must pin, always pin 2-3 headlines to the same position rather than just one. This preserves Google's ability to test which of your compliant options performs best, while still enforcing your requirement. A pin with only one option is a fixed ad — not a responsive one.

Power Words, Keyword Alignment, and What Not to Write

Power words that consistently drive higher CTR fall into predictable categories: urgency (Today, Now, Immediate, Same-Day), exclusivity (Limited, Exclusive, Only), proof (Certified, Award-Winning, Trusted by X), savings (Free, Save, No Fee), and specificity (any number or measurable fact). The best copy combines two or more of these in a single headline: "Same-Day Service — No Overtime Fee" hits urgency and removes a common objection in 34 characters flat.

Keyword alignment matters for two reasons: Quality Score and message match. When the search query matches language in your headline, Google bolds the matching words in the ad, which visually increases CTR. More importantly, users who see their search language reflected in the ad feel an immediate sense of relevance — the ad appears to be speaking directly to their need. Include your primary keyword in at least 2-3 of your 15 headlines, but vary the phrasing rather than repeating the same keyword phrase verbatim.

What not to write — policy and compliance traps: Google's editorial policies prohibit superlatives without substantiation (#1, Best in the World), misleading claims (Guaranteed Results in phrases that imply certainty), and certain industry-specific language. In healthcare ads, do not promise outcomes. In financial ads, avoid guaranteed returns. In legal ads, do not imply a case result. Beyond policy, avoid exclamation marks in headlines (Google often disapproves them) and ALL CAPS words (same issue). Write professional, clear copy that a reasonable person could read without feeling manipulated.

Ad Copy A/B Testing Methodology and Quality Score Impact

Quality Score is Google's 1-10 rating of your keyword-ad-landing page combination. It has three sub-components: expected click-through rate, ad relevance, and landing page experience. Ad copy directly influences the first two. A keyword with a Quality Score of 7 versus a Quality Score of 4 can cost 30-40% less per click while achieving the same or better ad position. That difference in copy quality compounds dramatically at scale.

RSA asset-level testing methodology: After running an RSA for 4-6 weeks with enough impressions to generate statistically meaningful data (generally 1,000+ impressions per headline), open the Assets report in Google Ads. Each asset will be rated: Best, Good, Low, or — (not enough data). Remove any assets rated Low after sufficient impressions and replace them with new variants. This is a continuous cycle, not a one-time event.

The most common testing mistake is changing too many variables at once. If you replace 6 headlines in a single edit, you cannot determine which change drove performance improvement or decline. Change 2-3 assets at most in any single iteration. Give each iteration 4-6 weeks before evaluating again.

Testing angles to prioritize: Lead with a different primary benefit (price vs. speed vs. quality). Test specific numbers against general claims (Save Up to 40% vs. Save More). Test urgency against proof (Call Today vs. Trusted by 2,000+ Homeowners). These represent genuinely different value propositions — not just word swaps — and they reveal what your audience actually responds to.