LinkedIn Ad Specs and File Requirements by Format
Specify format and dimensions upfront to avoid production delays and creative rejections.
LinkedIn ad specs and file requirements vary by format, so the brief needs to spell them out before production starts. A campaign launches cleanly when its creative is built for its format.
Why LinkedIn ad specs are a production problem, not a platform formality
A brief that asks for a “LinkedIn ad” leaves too much undecided. Sponsored Content includes single image, carousel, video, document, event, article and newsletter, and thought leader ads. Sponsored Messaging reaches members in their inboxes. Dynamic Ads personalize desktop placements using profile data, while Connected TV has its own production and campaign requirements. Locking the format and placement first gives production a usable brief, rather than a set of assumptions that can end in rejected creatives and delayed campaigns.
Single image ad specs: the feed workhorse and where truncation happens
Single image ads are the most common LinkedIn ad type, appearing in the desktop and mobile feed for awareness, engagement, and lead generation. Recommended dimensions include 1200 × 1200 px at a square ratio of 1:1, 1200 × 627 px at a landscape ratio of 1.91:1, and 1080 × 1350 px at a vertical ratio of 4:5. A square image takes up plenty of space in the mobile feed. Vertical takes up the most space in the mobile feed, while landscape is the standard horizontal option.
The writing constraint is less obvious than the image shape. Introductory text accepts up to 600 characters, but only approximately the first 150 appear before “see more” on mobile. The headline accepts 200 characters, yet truncates at approximately 70 on desktop, and the description allows 30. Write the proposition into the visible introduction and keep the headline’s hook within its visible portion.
Video ad specs: codec, caption, and aspect ratio requirements
Files must use the required container format with a supported video codec or VP8 video and AAC or MPEG4 audio, and can be no larger than 200 MB. Minimum resolution is 360p, with 1080p recommended. Supported aspect ratios are 16:9, 1:1, 4:5, and 9:16, with vertical formats taking more mobile screen space. Codec or ratio errors can mean a rejected upload or poor rendering.
Duration can range from 3 seconds to 30 minutes, although 15 to 30 seconds is the practical range for performance campaigns. Introductory text allows up to 600 characters, with approximately 150 visible, and a 70-character headline is recommended. Auto-generated captions exist, but uploading an SRT file gives control over accuracy for an audience predominantly watching without sound. Captions keep the message intelligible during muted playback.
Carousel ad specs: card-level requirements and the video exception
LinkedIn does not support video within Carousel Ads. Every card must be a static image, so this is not a format for combining image and video assets. A carousel contains 2 to 10 cards, accepts JPG or PNG, and allows up to 10 MB per card. All cards must have the same aspect ratio. Those requirements apply to every part of the sequence, whether it tells a step-by-step story or presents separate offers.
Copy limits also apply at card level. A card headline allows 45 characters when the card links to a URL, but only 30 when it does not. Introductory text follows Sponsored Content limits, with approximately 150 characters visible before “see more”. Each card can have a different destination URL. That makes the format useful for a product catalog in which each item needs its own landing page.
Document ad specs: file types, page limits, and the lead gen PDF requirement
A document ad paired with a Lead Gen Form must use a PDF. Teams building gated content in PowerPoint need to export it before upload, even though ungated document ads accept PDF, DOC, DOCX, PPT, and PPTX. The maximum file size is 100 MB, and the page limit is 300. Within that allowance, 10 to 20 pages tends to perform best. Members can read or scroll the file directly in the feed without leaving LinkedIn.
The uploaded file also determines the preview. LinkedIn generates it from the first page, so the cover must earn attention on its own. Embedded videos and animations render as static images, and multi-layer PDFs should be flattened before upload. The surrounding introduction accepts up to 600 characters, with approximately 150 visible. A 70-character headline is recommended.
Thought Leader Ad specs: inherited format rules and surrendered creative control
Thought Leader Ads get their specifications from an existing public organic post. Eligible sources are single image, video, or event posts, while document posts, polls, and multi-image posts are not supported. A boosted video follows video ad requirements, and a boosted image follows single image requirements.
That inheritance extends to the copy. The advertiser cannot add separate introductory text, a headline, or a CTA button. Any edits must be made to the original author’s post before the ad is created, and the employee whose post is being boosted must give permission. The author can revoke approval at any time, switching the ad off. Production therefore depends on both the source asset and permission to use it.
Event ad specs and article/newsletter ad specs: auto-populated formats
Event and article/newsletter ads use the main images from content already on LinkedIn. Event images use 1200 × 628 px at 1.91:1, accept JPG or PNG, and allow up to 5 MB. The advertiser’s main creative task is the introductory text that drives registrations. Article and newsletter ads automatically pull the featured image and headline at a 1.91:1 aspect ratio, leaving the advertiser to write an introduction with context or a specific call-to-action. These formats reduce asset creation, but the source content determines much of what appears in the ad.
Click-to-Message ad specs: single image format with inbox delivery
Click-to-Message ads use the same image dimensions as single image Sponsored Content, and the click opens a LinkedIn conversation. The recommended image is 1200 × 1200 px at 1:1, in JPG or PNG, with a maximum file size of 5 MB. That shared shape can make an existing single image asset reusable. The destination, however, is different. The advertiser customizes the opening message at campaign level, so reusing the image does not mean reusing the same post-click experience or objective assumptions.
Message Ad and Conversation Ad specs: inbox formats and the desktop-only banner
Message Ads allow a subject line of 60 characters, a message body of 1,500 characters, and CTA button text of 20 characters. Their banner is 300 × 250 px and can have a file size of up to 2 MB.
Conversation Ads use a different copy structure. Introductory text allows up to 500 characters, and each message can include up to 5 CTA buttons with 25 characters each. Each button can open a different follow-up message or an external URL, creating branching paths. The banner specifications match Message Ads. An inbox brief must account for different components as well as different dimensions.
Text Ad and Dynamic Ad specs: desktop-only formats with tight copy limits
Text Ads and Dynamic Ads are desktop-only, so they do not reach the mobile portion of an audience. Text Ads use a 100 × 100 px image in JPG or PNG, with a maximum file size of 2 MB. Their headline allows 25 characters and their description allows 75.
Follower and Spotlight Dynamic Ads allow a 50-character headline and a 70-character description. Spotlight also supports an optional 300 × 250 px background image and an 18-character CTA button. Job ads auto-populate from the job posting. Across this family, the desktop restriction matters as much as the character count. A mobile-heavy campaign cannot treat these placements as substitutes for mobile feed ads.
Connected TV ad specs: the format that requires its own separate campaign
Connected TV launched in 2024 and requires video at a 16:9 aspect ratio only. Its production bar is closer to broadcast television than to digital display, with broadcast-grade bitrate and resolution requirements. Frame rate is also part of that higher production standard. A familiar video file type or horizontal shape alone does not make an asset suitable for CTV.
The hard boundary is between CTV and non-CTV production. Video ads created for non-CTV campaigns cannot be repurposed for this format, so assets must be produced specifically for it. Connected TV also needs a campaign of its own.
Lead Gen Form specs: the attachment that changes what any format collects
Lead Gen Forms are attachments. They take the place of a landing page on Sponsored Content and Sponsored Messaging formats that support them, so members can share their information without leaving LinkedIn. The underlying ad still has its own asset requirements.
A form allows 60 characters for its headline, 70 for its description, and 160 for its introductory text. The privacy policy disclaimer allows up to 2,500 characters, and a form can contain up to 12 fields. LinkedIn pre-fills fields with member profile data, which makes the form easier to fill out and usually means more members finish it. The important distinction is between producing the ad and configuring what its attached form collects.
The production mistakes that cause the most rejections and rendering failures
The pre-production check starts with the promise and where it appears. Before writing the brief, check that the proposition is in the visible copy so readers can see it without opening the expanded text. Then check that the chosen placement reaches people on the devices they use. This catches two different failures early, namely copy that is accepted but hidden and creative built for a desktop-only placement when the audience is mobile-heavy.
A carousel brief needs static cards with the same ratio, while a document brief cannot rely on embedded movement to get the message across. Gated document production needs the correct export, and video production needs an accurate caption deliverable. CTV needs its own assets and campaign plan. These checks belong before the handoff because they change what the team must make.
How AI-powered platforms handle LinkedIn spec compliance and campaign execution at scale
Teams must keep track of the requirements, resize assets, and check how ads perform across placements, often using separate tools. That fragmented workflow creates room for specification errors as one approved concept becomes several production files. The challenge shifts from deciding what to say to executing it correctly across ratios, audiences, and formats.
AI-powered ad platforms bring creative automation, multi-channel campaign management, and performance monitoring into one interface to help with that work. This reduces the need to stitch together separate spec-checking tools, resizing apps, and analytics dashboards. The value is a less fragmented production process under the same LinkedIn rules. Automation can help carry an approved campaign across placements, but the starting decision remains the same. Choose the format before asking the production team to make the asset.
