Headline analyzer
What is ad headline truncation?
Ad headline truncation is where a platform accepts a longer headline than it actually shows, then clips the rest at render time. Facebook’s mobile feed recommends about 27 characters before the headline is cut; LinkedIn Sponsored Content single-image ads allow up to 70 characters, displayed without a "see more" expander. So unlike Google’s hard 30-character upload cap, the effective ideal on Meta and LinkedIn is the visible slot — write the whole promise inside it.
Seeklyn shows the per-platform visible window as a live marker in the Ads channel of the Headline Studio — the ~27-character Facebook-feed line and the 70-character LinkedIn line — so you can see where your headline gets clipped on each surface.
How is this different from Google’s hard cap?
Google enforces a hard limit: a Responsive Search Ad headline over 30 characters is rejected at upload, so the constraint is a wall. Meta and LinkedIn work differently — they accept a longer string, then only display a window of it, clipping the rest. That makes the real constraint the visible slot rather than the accepted maximum. A headline that technically fits the upload limit but overruns the display window is truncated exactly where the reader is looking, so the "ideal length" is effectively the number of characters the surface actually shows.
On Facebook’s mobile feed, the official ads guide recommends about 27 characters for the headline, with practical hard clipping near 40; the tail simply disappears in the feed. LinkedIn Sponsored Content single-image ads allow up to 70 characters in the headline and up to 150 in the introductory text — and critically, the 70-character headline is shown without a "see more" expander, so anything you write up to 70 is visible but nothing beyond it survives. The rule of thumb: fit the message inside the smallest window you care about, and put brand tags or qualifiers where a cut does no harm.
| Platform / surface | Accepted headline | Effective visible window |
|---|---|---|
| Google RSA (search) | 30 (hard cap) | 30 — rejected at upload if over |
| Facebook mobile feed | ~40 (clips) | ~27 recommended before the cut |
| LinkedIn Sponsored Content | 70 | 70, no "see more" — all shown or gone |
How do you write to the visible slot?
Front-load the offer and the hook so they land inside the tightest window your campaign uses, and treat the maximum as headroom, not a target. On Facebook’s feed, aim for the ~27-character recommendation so nothing is clipped on mobile; on LinkedIn, you have a genuine 70 characters to work with, but every one of them is on screen, so make them count rather than padding. When the same creative runs across platforms, write to the smallest visible slot first, then extend only where a surface actually shows more.
Sources & evidence
- Meta (Facebook) Ads Guide — Feed image ad specs — Facebook feed recommends ~27 characters for the headline.
- LinkedIn — Single Image Ad specifications — Sponsored Content headline up to 70 characters; introductory text up to 150.
Frequently asked questions
What is the ideal Facebook ad headline length?
About 27 characters. Facebook’s official ads guide recommends ~27 characters for the mobile-feed headline; longer headlines are accepted but clipped near 40, so the visible window is what matters.
How long can a LinkedIn Sponsored Content headline be?
Up to 70 characters, and all 70 are displayed without a "see more" expander. Introductory text allows up to 150 characters. Anything past 70 in the headline is simply not shown.