What Are Google Ads' Character Limits for Responsive Search Ad Headlines and Descriptions?

A Google Ads responsive search ad (RSA) allows up to 15 headlines, each capped at 30 characters, and up to 4 descriptions, each capped at 90 characters, according to Google's official support documentation. You don't have to fill every slot, but Google recommends using as many as you can so its system has more combinations to test.

The Exact Limits

• Headlines — up to 15 per ad, 30 characters maximum each.
• Descriptions — up to 4 per ad, 90 characters maximum each.
• Paths — two optional display-path fields that append to your final URL, 15 characters maximum each.

Not Every Headline or Description Is Guaranteed to Show

Google Ads only guarantees that your ad will display the first headline position and first description. The second and third headline positions, and the second description, are filled based on what Google's system predicts will perform best for that specific search query — meaning a given headline you wrote might never appear together with another one you wrote, even if both are approved and active. This is why Google recommends writing headlines that each make sense as a standalone statement rather than ones that depend on a neighboring headline to read correctly.

Double-Width Languages Count Differently

For languages that use double-width characters — Chinese, Japanese, and Korean are the ones Google calls out specifically — every character counts as two toward the limit instead of one. A 30-character headline limit effectively becomes a 15-character limit in those languages, which catches advertisers off guard when they translate English ad copy directly instead of rewriting for the shorter effective length.

Why the Limits Exist

Responsive search ads work by letting Google's machine learning test different combinations of your headlines and descriptions against different queries and audiences, then serving whichever combination it predicts will perform best for that specific search. Capping each individual asset at a fixed character count keeps every combination within Google's ad layout constraints across all the surfaces an ad can appear on — standard search results, Shopping-adjacent placements, and partner search sites — without needing per-surface length rules.

What Happens If You Go Over

Google Ads won't let a headline or description past its character cap; typing beyond the limit in the Google Ads interface either blocks additional characters or flags the asset as invalid before it can be saved, rather than truncating it silently after publishing.

Bottom Line

Use all 15 headline slots and all 4 description slots where you can, keep each one readable as a standalone line since Google decides which combinations actually get shown, and double-check effective character counts if you're running ads in Chinese, Japanese, or Korean.

Source: Google Ads Help, "About responsive search ads" (support.google.com/google-ads/answer/7684791).