The Complete Guide to LinkedIn Paid Ad Specs: Dimensions, Formats, and Best Practices

When running B2B campaigns, a great strategy can easily stall out if your creative assets fail technical checks or look awkwardly cropped in the professional feed. LinkedIn’s ad platform operates on precise requirements, and matching your design work to the right specifications is critical for maintaining brand credibility and driving performance.

This comprehensive guide breaks down the essential technical specs, character counts, and design best practices for every major LinkedIn paid ad format.

1. Single Image Ads

Single image ads are the backbone of B2B campaigns—ideal for driving website traffic, generating leads, or sharing high-impact thought leadership graphics.

• Landscape (1.91:1):
  • Recommended Size: 1200 × 628 px
  • File Formats: JPG, PNG, GIF
  • Max File Size: 5 MB
• Square (1:1):
  • Recommended Size: 1200 × 1200 px (Great all-rounder for cross-platform delivery)
  • File Formats: JPG, PNG, GIF
  • Max File Size: 5 MB
• Vertical / Portrait (4:5):
  • Recommended Size: 720 × 900 px (Maximizes mobile feed space)
  • File Formats: JPG, PNG, GIF
  • Max File Size: 5 MB

Copy Constraints:

• Intro Text: Up to 150 characters recommended (though truncation varies).
• Headline: Up to 70 characters.

2. Video Ads

Video is unmatched for product demos, customer testimonials, and brand storytelling. LinkedIn supports multiple aspect ratios to accommodate how professionals hold their devices.

• Landscape (16:9): 1920 × 1080 px
• Square (1:1): Up to 1920 × 1920 px
• Vertical (4:5): 720 × 900 px (Recommended for mobile feeds)
• Full Vertical (9:16): 1080 × 1920 px

Technical Requirements:

• File Format: MP4
• File Size: 75 KB to 500 MB
• Duration: 3 seconds to 30 minutes (though high-converting B2B videos usually stay under 30–90 seconds).
• Frame Rate: 30 FPS or lower recommended.
• Thumbnails: JPG or PNG matching your video’s aspect ratio (max 2 MB).

3. Carousel Ads

Carousel ads allow you to showcase a sequence of up to 10 cards, making them ideal for step-by-step frameworks, feature breakdowns, or multi-stat proof points.

• Card Dimensions: 1080 × 1080 px (Square, 1:1)
• Number of Cards: 2 to 10 cards
• File Formats: JPG, PNG, or non-animated GIF
• Max File Size: 10 MB per card

Copy Constraints:

• Card Headline: Up to 45 characters.
• Intro Text: Up to 255 characters.

4. Document Ads

Document ads let users read long-form assets—such as whitepapers, e-books, or research reports—directly inside the LinkedIn feed without navigating away to a landing page.

• Accepted File Types: PDF, PPT, PPTX, DOC, DOCX
• Max File Size: Up to 100 MB
• Page Limit: Up to 300 pages (though shorter, punchier guides usually yield higher completion rates).

5. Thought Leader Ads

Thought Leader Ads amplify organic posts written by real people (such as your company executives, subject matter experts, or creators) rather than just a faceless brand page.

• Specs: Because they sponsor existing organic content, they inherit the base specs of the underlying format (Single Image or Video). Ensure the original organic post is optimized with clean dimensions before initiating sponsorship from Campaign Manager.

6. Conversation & Message Ads

Direct-response messaging formats deliver personalized content straight to a target prospect’s LinkedIn InMail inbox.

• Message Text: Up to 8,000 characters
• Call-to-Action (CTA) Button: Up to 25 characters
• Custom Footer/Legal Text: Up to 20,000 characters
• Optional Desktop Banner: 300 × 250 px (JPG or PNG, max 2 MB)

7. Dynamic Ads (Spotlight & Follower Ads)

Dynamic ads automatically personalize themselves using the target user’s profile data (such as their name, profile photo, and job title).

• Company Logo: 100 × 100 px (JPG or PNG, max 2 MB)
• Spotlight Background Image (Optional): 300 × 250 px (max 2 MB)
• Headline: Up to 50 characters
• Description: Up to 70 characters
• CTA Button: Up to 18 characters

Quick Checklist for a Smooth Launch

1. Design Mobile-First: Over 60% of LinkedIn traffic occurs on mobile devices. Square (1:1) and vertical (4:5) assets occupy significantly more feed real estate than landscape alternatives.
2. Double-Check Text Truncation: Keep critical value propositions and branding elements away from the absolute edges of your creative assets to account for UI overlays.
3. Align with Lead Gen Forms: If you are pairing your ads with LinkedIn Lead Gen Forms, keep form fields minimal (3–4 fields is the sweet spot) to maximize completion rates.