LinkedIn Ad Specs: Every Size and Character Limit

Search for LinkedIn ad specs and most of what comes back is a blog post from three years ago that was copied off another blog post. A designer builds to it. Campaign Manager rejects the upload. The launch slips a day, and nobody can say for certain which number was wrong.

So this is the reference sheet we keep for ourselves. Every figure below came out of LinkedIn's own advertising specifications, checked in September 2026: image dimensions, aspect ratios, file size caps, video length, and the character limits for headline, introductory text and description, format by format.

I'm Raphael Presberg, Founder and CEO of Moriah, a LinkedIn marketing agency and a LinkedIn Certified Marketing Partner. LinkedIn Ads are one of three pillars we run for established B2B companies, next to executive personal branding and targeted outreach. We always run the three together, because that combination is what actually turns LinkedIn into business.

One thing this page deliberately won't do is explain what each format is for. Different question, and it has its own page. If you're still choosing a format, read types of LinkedIn ads first, then come back here to build it.

Hard Limits and Soft Limits Are Not the Same Thing

Almost every specs list skips this distinction, and it's the one that bites when you're writing copy.

Hard limits are enforced by Campaign Manager. Go over and the ad won't save, or the file won't upload. File size caps, pixel minimums and maximums, card counts, page counts, the absolute character maximums: all hard.

Soft limits are display limits. LinkedIn takes the ad, publishes it, then chops the text off in the feed behind a "see more" link. A 200 character headline is perfectly legal. It just won't get read.

Single image ads are the obvious case. The headline maximum is 200 characters, while LinkedIn's own guidance says 70 to avoid truncation. Introductory text accepts up to 3,000 and starts cutting around 150. Where the cut actually lands shifts by device and placement, so treat the truncation figure as your real budget and the maximum as a ceiling you never go near.

Truncation figures come first in the tables below, because that's the number to write to.

LinkedIn Ad Sizes at a Glance

The image and file requirements for every format, in one place.

Two traps hide in that table. Single image files narrower than 401 pixels render as a small thumbnail instead of a full-width image, so clearing the 360 pixel minimum doesn't get you the placement you had in mind. And the spotlight background has to be exactly 300 x 250. Not roughly. Anything else is rejected.

Sponsored Content Specs

The formats that show up in the feed.

Single Image Ads

That description field only surfaces on LinkedIn Audience Network placements, and it can be cut shorter there than the 100 character guidance implies. Running feed-only? Ignore it. Animated GIFs are fine up to 250 frames.

Video Ads

Three operational details the numbers don't tell you. Any video under 30 seconds loops until 30 seconds of playback has been filled, so a 10 second clip plays three times over. The file has to go up to LinkedIn directly; you can't point it at YouTube or Vimeo. And Campaign Manager only takes 25 video uploads in any 24 hour period, which is a limit you want to know about the week before a big launch rather than the morning of.

The 30 minute maximum is real and close to useless. Nobody sits through a 30 minute ad. We write to the 15 to 30 second figure.

Carousel Ads

Giving the card headline limit in lines rather than characters is unhelpful, until you accept what it means in practice: write short, then check it on a phone. Every card in the set has to share the same ratio. Full detail on the format sits on our LinkedIn carousel ads page.

Document Ads

PDFs want to be flattened, with every page the same size. Video and animation get stripped out. Hyperlinks inside the document only work once the reader has downloaded it, which is where this format disappoints people most often: that call to action on page 12 does nothing in the in-feed preview.

Event Ads

LinkedIn publishes a 600 character maximum for introductory text on event ads, plus a 255 character ad name, and no separate image dimensions at all. By default the ad carries the LinkedIn Event's own cover image; pick something from your media library and that replaces it. Date, time and the registration button are generated from the event itself rather than written by you. See LinkedIn event ads for how the format behaves.

Thought Leader Ads

Thought leader ads barely have specs of their own, because you're promoting a post that already exists instead of building a creative.

• You can't write a headline or introductory text. The post's own copy is the ad copy, and only the original author can edit it.
• There's no call to action button, with the exception of event ads, which keep theirs.
• Supported underlying formats: text-only, single image, video, event, and article or newsletter posts.
• Supported objectives: brand awareness and engagement, with video views also available when the underlying post is a video.
• Posts containing multiple images, a poll, a document, or a celebration can't be promoted this way. Neither can a repost: only the original author's post is eligible.

That last restriction catches people out. A strong carousel post from an executive isn't eligible.

Sponsored Messaging Specs

These land in the LinkedIn inbox.

Message Ads

The banner is desktop only, and genuinely optional. More on the format on our LinkedIn message ads page.

Conversation Ads

One of those five buttons per message is the automatic "Not Interested" option, so in practice you're designing four branches at every step. And 8,000 characters per layer is a hard limit, not an invitation.

Text, Spotlight and Follower Ad Specs

The right rail formats. Desktop only.

Text Ads

Text ads render at a handful of sizes depending on placement: 300 x 250, 700 x 17, 160 x 600, 728 x 90 and 496 x 80. Twenty five characters for a headline is the tightest limit LinkedIn imposes anywhere, and it's hard, not a truncation point.

Spotlight Ads

Add a custom background and you lose both the description and the member's profile photo from the unit, which strips out the personalization that makes the format work in the first place. The usable white content area inside it measures 276 x 148 px. Our LinkedIn spotlight ads page covers that trade-off in full.

Follower Ads

Write custom text, or pick from LinkedIn's suggested options. The member's profile photo and first name are inserted automatically.

Lead Gen Form Specs

Lead Gen Forms attach to several formats rather than standing alone, so their limits stack on top of whatever the host format allows.

Custom questions count against the 12 field maximum. Custom checkboxes don't. A privacy policy URL is required, not optional. For what actually belongs in those 12 fields, see LinkedIn lead gen forms.

What We Do With These Numbers

Specs are the floor, not the strategy. Get every limit right and the ad gets approved. That's all it gets you.

At Moriah, LinkedIn Ads run alongside executive personal branding and targeted outreach, as one business engine rather than three campaigns that happen to share a logo. That ordering shows up in the creative you're about to build. An ad from a company nobody in the feed recognizes has to do all of its work cold. The same ad, landing on an audience that has been reading the founder's posts for two months and has already had a real conversation with the sales team, is doing something much easier. Identical format specs. Very different result.

The practical version: write to the truncation figure, not the maximum. Build the 1:1 square first, since it serves on desktop and mobile and still takes more feed space than landscape, then add a 4:5 vertical if the weight of the budget is going to mobile. Keep video to 30 seconds. And settle what the ad is supposed to achieve before you open the design file, because the objective you pick in Campaign Manager restricts which of these formats you're allowed to run at all.

Frequently Asked Questions

What are the LinkedIn ad specs for a single image ad? Up to 5 MB, as a JPG, PNG or GIF, at 1200 x 628 for landscape, 1200 x 1200 for square, or 720 x 900 for vertical. Write 150 characters of introductory text and a 70 character headline to stay clear of truncation in the feed.

What is the best LinkedIn ad size? LinkedIn recommends vertical ratios for single image ads and suggests 4:5, at 720 x 900, to avoid borders, but paid vertical assets only serve on mobile. Producing one asset for everything? 1200 x 628 landscape is the safest choice, because it delivers on desktop and mobile. 1200 x 1200 square also runs on both, and occupies more feed space than landscape.

How long can a LinkedIn video ad be? Between 3 seconds and 30 minutes, with in-stream video ads capped at 90 seconds. LinkedIn recommends 15 to 30 seconds, and anything under 30 seconds loops until 30 seconds of playback has been reached.

What is the LinkedIn ad character limit for a headline? Sponsored Content headlines accept up to 200 characters but truncate past roughly 70. Text ads are capped hard at 25 characters, spotlight and follower headlines at 50, and message ad subject lines at 60.

What is the maximum file size for a LinkedIn ad? Single images are 5 MB, carousel cards 10 MB each, videos 500 MB, documents 100 MB, and banner or right-rail images 2 MB. All hard limits, and the upload fails above them.

How many cards can a LinkedIn carousel ad have? Between 2 and 10. Every card has to use the same 1:1 ratio, with 1080 x 1080 recommended and a 10 MB cap per card.

Do LinkedIn ad specs differ between desktop and mobile? The upload requirements are the same. Placement and display are not. Vertical 4:5 and 9:16 assets only serve on mobile, while text, spotlight and follower ads are desktop only. Text truncation also tends to hit earlier on narrower screens.

What file types does LinkedIn accept for ads? JPG, PNG and GIF for images, though carousel cards reject animated GIFs. MP4 for video. PDF, PPT, PPTX, DOC and DOCX for document ads, with PDF the only option under a lead generation objective.

What happens if I go over a LinkedIn character limit? Depends which limit. Exceeding an absolute maximum stops the ad saving in Campaign Manager. Exceeding a truncation figure publishes fine, and simply cuts the text off in the feed behind a "see more" link.

Where do these LinkedIn ad specs come from? Every figure on this page is taken from LinkedIn's own advertising specifications in the Marketing Solutions help center, checked in September 2026. LinkedIn revises them without announcing it, so confirm anything critical in Campaign Manager before a large production run.