ScaleyResponsive Search Ads (RSA) in Google Ads
The standard Search ad today. How Google mixes your lines, the limits for each field, when to pin, and how many to run in one ad group.
Written and reviewed by Christopher Krassnig
Published Last checked
A responsive search ad (RSA) is the standard Search ad in Google Ads. You write up to 15 headlines and 4 descriptions, and Google mixes them into ads that fit each search. Headlines can be 30 characters, descriptions 90. You need at least 3 headlines and 2 descriptions to save one.
Also called: RSA, RSAs
How Responsive Search Ads Work
You write the parts. Google builds the ad. Google says it "assembles the text into multiple ad combinations in a way that avoids redundancy" and, over time, "will test the most promising ad combinations".
Each time your ad shows, Google picks at least one headline and one description, and can show up to 3 headlines in the headline spot. Words that match the search can appear in bold.
Because the parts appear in any order, Google's advice is to make each one "make sense individually or in combinations".
Responsive Search Ad Limits
Google's numbers for each field:
| Field | How many | Characters each |
|---|---|---|
| Headlines | At least 3, up to 15 | 30 |
| Descriptions | At least 2, up to 4 | 90 |
| Display path | 2 fields | 15 |
In double-width languages like Korean, Japanese or Chinese, every character counts as 2.
Pinning: When and When Not
Pinning locks a line to one spot, like Headline position 1. Google says text that must be in every ad, like a legal line, has to be pinned to Headline position 1, Headline position 2 or Description position 1.
Pin as little as you can. Google says pinning "isn't recommended for most advertisers" because it cuts the number of combinations and can lower Ad Strength. If you must pin, Google suggests pinning 2 or 3 different lines to the same spot so it can still test.
How Many Responsive Search Ads per Ad Group
Google's tip is "at least 2 responsive search ads (RSA) with 'Good' or 'Excellent' Ad Strength per ad group", each with its own final URL. Google reports that advertisers going from 1 RSA to 2 saw 6.6% more conversions on average at a similar cost per conversion. Those are Google's own averages, not a promise for your account.
Responsive Search Ads vs Dynamic Search Ads
An RSA uses the headlines you write and shows on your keywords. A Dynamic Search Ad wrote its headline from your website and chose searches from your site's content, with no keywords. Google is upgrading Dynamic Search Ads to AI Max, so for new campaigns the RSA is the ad you will write.
Example: A Tea Store Writes Its First RSA
Made-up copy, to show the method. A tea store writes 12 headlines for its matcha ad group. Three carry the keyword ("Organic Matcha Powder", "Ceremonial Grade Matcha", "Matcha From Uji, Japan"). Three carry the offer ("Free Shipping Over $40", "30-Day Taste Promise", "Starter Kits From $19"). The rest carry proof and benefits.
It writes 4 descriptions under 90 characters each, all making sense on their own. It pins nothing. It adds a second RSA with a different angle ("Matcha Latte at Home") pointing at a recipe landing page.
Four weeks later it checks the Assets report and swaps out the headlines Google rates lowest.
Common Mistakes
15 headlines that say the same thing
Google wants unique lines. Ten ways to say "Buy Matcha" gives it nothing to test.
Pinning everything
If every position is pinned, unpinned lines never show and the ad stops being responsive.
Lines that need each other
Headline 2 might show without Headline 1. Each line has to make sense alone.
Phone numbers in the text
Google's editorial policy does not allow a phone number in ad text. Use a call asset.
Questions People Ask
You write the headlines for a responsive search ad, and it shows on your keywords. A dynamic search ad got its headline and searches from your website. Google is upgrading Dynamic Search Ads to AI Max.
Google's Own Pages We Quoted
Every rule, limit and size on this page comes from these pages, read on 8 October 2026. Google changes them, so check the page itself before you act.
Where to Go Next
- What Is Ad Copy?How to write the lines an RSA is built from.
- Google AI Max for SearchText customization can write extra RSA lines for you.
- What Is Quality Score?Ad relevance is one of its three parts.
- Google Ads Transparency Center: How to See Any Advertiser's AdsSee the headlines your rivals run before you write yours.
Ask Where Your Ad Money Went
Connect read-only in under five minutes. Ask which search terms and products lost money last month. Not ready to connect? The two-minute quiz scores you with no Google Ads login.
3-day free trial. Card required. Cancel anytime