A Responsive Search Ad (RSA) is Google's default search ad format. You supply up to 15 headlines (30 characters each) and 4 descriptions (90 characters each), and Google's machine learning assembles and tests combinations — showing up to 3 headlines and 2 descriptions per impression — to maximize performance for each query.
RSAs replaced Expanded Text Ads as the only standard search ad type advertisers can create in Google Ads since June 2022. The core idea is combinatorial: instead of writing one fixed ad, you provide assets and let Google test thousands of combinations against real queries. With 15 headlines and 4 descriptions there are over 43,000 possible combinations, which is why asset variety matters more than perfecting one line.
Google scores your asset set with an Ad Strength rating (Poor, Average, Good, Excellent). The rating rewards filling all 15 headline slots, keyword relevance in at least a few headlines, and variety — headlines that say the same thing in different words count against you. Excellent Ad Strength is not a ranking factor by itself, but Google's own data shows advertisers who improve Ad Strength from Poor to Excellent see roughly 12% more conversions on average, mostly because more usable combinations qualify for more auctions.
In practice, a strong RSA mixes headline roles: 3–4 keyword-focused headlines that mirror what users type, 3–4 benefit headlines, 2–3 with proof or numbers, 2 with a call to action, and 1–2 brand headlines. Descriptions should each work standing alone, because you never control which two appear together.
Pinning lets you lock an asset to position 1, 2, or 3 when compliance or brand rules demand it, but every pin reduces the combinations Google can test — pin only what legal or brand requirements force you to. One practical workflow: generate a full 15-headline set, check every line against the 30-character limit, and replace near-duplicates before launch — that single pass typically moves Ad Strength from Average to Good or better.
For a project-management SaaS, three RSA headlines with distinct roles: "Project Management Tool" (keyword, 23 chars), "Plan Sprints In Minutes" (benefit, 23 chars), "Trusted By 12,000 Teams" (proof, 23 chars). Google might pair any of them with the description "Drag-and-drop boards, timelines, and reports. Start free — no credit card required." (84 chars).
All 15 if you can write genuinely distinct ones. Ad Strength explicitly rewards filling the slots, but 12 distinct headlines beat 15 where 6 are paraphrases of each other — variety across keyword, benefit, proof, and CTA roles is what unlocks combinations.
Yes. Headlines are capped at 30 characters and descriptions at 90 characters including spaces and punctuation. With Dynamic Keyword Insertion, the counted length is the fallback text, not the DKI syntax itself.
Only when something must always show — legal disclaimers, regulated claims, or strict brand rules. Each pin shrinks the testing pool; Google's guidance and most agency tests show unpinned RSAs usually win on conversions.