Cracking the Code: The Ultimate Guide to LinkedIn Paid Ad Specs

Running campaigns on LinkedIn offers an unparalleled opportunity to target decision-makers, industry experts, and B2B buyers. However, nothing halts a high-performing marketing campaign faster than a rejected creative asset or a distorted image layout. LinkedIn’s ad review system and technical parameters are notoriously strict, meaning that hitting the exact pixel dimensions, file formats, and character caps is non-negotiable.

Whether you are launching single-image sponsored updates, immersive video campaigns, or text ads, this comprehensive breakdown covers the technical blueprints you need to get your ads approved and performing at their peak.

1. Single Image Ads (Sponsored Content)

Single image ads appear directly in the LinkedIn feed, blending native posts with high-impact promotions. They are versatile and support three primary aspect ratios depending on how much screen real estate you want to command.

• Square (1:1):
  • Recommended Resolution: 1200 x 1200 px
  • Delivery: Desktop and mobile feeds
• Landscape (1.91:1):
  • Recommended Resolution: 1200 x 628 px
  • Delivery: Desktop and mobile feeds
• Vertical (4:5):
  • Recommended Resolution: 720 x 900 px
  • Delivery: Mobile feed only (takes up maximum vertical space)
• Technical Constraints:
  • File Formats: JPG, PNG, or GIF (non-animated)
  • Max File Size: 5 MB
• Copy Limits:
  • Introductory Text: 150 characters recommended (though truncation occurs past roughly 150–220 depending on placement)
  • Headline: 70 characters (ideal for keeping messages punchy)

2. Video Ads

Video is a dominant medium for brand awareness and deep-dive product explainers on LinkedIn. To avoid letterboxing or awkward cropping, match your export settings to LinkedIn’s native ratios.

• Supported Aspect Ratios & Production Sizes:
  • Landscape (16:9): 1920 x 1080 px
  • Square (1:1): Up to 1920 x 1920 px
  • Vertical (4:5): 720 x 900 px (Recommended for mobile feeds)
  • Vertical (9:16): 720 x 1280 px up to 1080 x 1920 px
• Technical Constraints:
  • File Format: MP4
  • File Size: 75 KB to 500 MB
  • Duration: 3 seconds to 30 minutes (though high-performing B2B ads typically sit between 15 to 30 seconds)
  • Frame Rate: 30 FPS recommended
  • Thumbnails: Custom JPG or PNG, max 2 MB, matching the aspect ratio of the video.

3. Carousel Ads

Carousels allow you to display a sequence of 2 to 10 swipeable cards, making them ideal for step-by-step guides, product features, or multi-angle storytelling.

• Card Dimensions: 1080 x 1080 px (1:1 aspect ratio)
• Technical Constraints:
  • File Formats: JPG, PNG, or non-animated GIF
  • Max File Size: 10 MB per card
• Copy Limits:
  • Card Headline: 45 characters (for destination URLs attached to cards)
  • Introductory Text: Up to 255 characters

4. Document Ads

If you are gating a high-value whitepaper, report, or case study, Document Ads allow users to preview and flip through a PDF or PowerPoint file directly inside their LinkedIn feed without navigating away.

• Supported File Types: PDF, DOC, DOCX, PPT, PPTX
• Max File Size: 100 MB
• Page Limit: Up to 300 pages (though 5–15 pages typically yield the highest engagement)

5. Conversation and Message Ads

These formats deliver direct, personalized messages straight to a user’s LinkedIn Messaging inbox.

• Message Text: Up to 1,500 characters for Message Ads; up to 8,000 characters for complex branching Conversation Ads.
• Call to Action (CTA) Button: Up to 20–25 characters.
• Optional Companion Banner: A 300 x 250 px JPG or PNG (max 2 MB) that displays on the desktop right-rail while users view your message.

6. Text and Spotlight Ads (Desktop Right-Rail)

Text and Spotlight ads are classic desktop-only formats that live on the right-hand side of the LinkedIn interface, prized for keeping brand awareness consistent at a low cost.

• Text Ads:
  • Logo Image: 100 x 100 px (JPG or PNG, max 2 MB)
  • Headline: Up to 25 characters
  • Description: Up to 75 characters
• Spotlight Ads:
  • Logo Image: 100 x 100 px (JPG or PNG, max 2 MB)
  • Custom Background Image (Optional): 300 x 250 px (max 2 MB)
  • Headline: Up to 50 characters
  • Description: Up to 70 characters

Pro-Tips for Seamless Ad Approval

1. Watch the Text Overlay: While LinkedIn no longer strictly enforces the old “20% text rule” algorithmically, heavily cluttered images still suffer in delivery quality and user trust. Keep visual text clean and legible.
2. Double-Check Safe Zones: For vertical videos and mobile feeds, keep vital text, logos, and CTAs away from the very top and bottom edges where UI elements (like profile names and reaction buttons) overlay the creative.
3. Always Add UTM Parameters: Ensure your destination URLs feature clean tracking tags so you can properly attribute leads and conversions back to individual formats in your CRM.