The Complete Guide to LinkedIn Paid Ad Specifications

Running B2B campaigns on LinkedIn without checking the technical blueprint is a quick way to burn budget. Ad formats that look pristine in a design suite can easily get clipped, rejected, or awkwardly resized if they miss LinkedIn’s strict technical thresholds.

Whether you are launching single image lead-gens, document carousels, or high-impact video ads, this guide covers the exact dimensions, file sizes, and character limits required for success on the platform.

1. Single Image Ads

Single image ads appear natively in the LinkedIn feed. They are your primary vehicle for direct-response and brand awareness campaigns.

• Aspect Ratios & Recommended Sizes:
  • Landscape (1.91:1): $1200 times 627$ px (Min. $640 times 360$ px)
  • Square (1:1): $1200 times 1200$ px (Min. $360 times 360$ px)
  • Vertical (4:5): $720 times 900$ px (Min. $360 times 640$ px) — Mobile-only delivery
• File Types: JPG, PNG, or non-animated GIF
• Max File Size: 5 MB
• Introductory Text: Up to 150 characters recommended before truncation (3,000 max)
• Headline: Up to 70 characters recommended before truncation (200 max)

2. Carousel Image Ads

Carousel ads allow you to feature 2 to 10 swipeable cards, making them ideal for step-by-step frameworks, product features, or sequential storytelling.

• Card Aspect Ratio: 1:1 Square
• Recommended Resolution: $1080 times 1080$ px (Max. $4320 times 4320$ px)
• File Types: JPG or PNG (non-animated GIFs allowed)
• Max File Size: 10 MB per card
• Introductory Text: Up to 255 characters
• Card Headline: Up to 45 characters (typically truncates after two lines)

3. Video Ads

Video ads capture immediate attention in the feed, driving deep engagement for product demos, customer stories, and brand messaging.

• Aspect Ratios & Resolutions:
  • Landscape (16:9): $1920 times 1080$ px
  • Square (1:1): $1920 times 1920$ px (Max)
  • Vertical (4:5): $1080 times 1350$ px
  • Vertical (9:16): $1080 times 1920$ px
• File Format: MP4
• Frame Rate: Up to 30 fps
• File Size Range: 75 KB to 500 MB
• Duration: 3 seconds to 30 minutes (Best performance is typically achieved between 15 and 30 seconds)
• Thumbnail: JPG or PNG, matching the video’s exact aspect ratio, up to 2 MB

4. Document Ads (Thought Leadership & Content Offers)

Document ads let users read whitepapers, reports, or guides directly within the LinkedIn feed without navigating to an external landing page.

• File Formats: PDF, DOC, DOCX, PPT, or PPTX
• Max File Size: 100 MB
• Page Limit: Up to 300 pages (Recommended layout: Letter, A4, or Legal)
• Introductory Text: Up to 150 characters recommended before truncation (3,000 max)
• Headline: Up to 70 characters recommended

5. Sponsored Messaging (Message & Conversation Ads)

Delivered straight to a user’s LinkedIn Messaging inbox, these formats provide a direct, high-intent channel for event invites and high-value resource distribution.

• Sender Image: Automatically pulled from the sender’s personal profile
• Subject Line: Up to 60 characters
• Message Text:
  • Message Ads: Up to 1,500 characters
  • Conversation Ads: Up to 8,000 characters per message layer
• Call-to-Action (CTA) Button: Up to 25 characters
• Optional Companion Banner (Desktop Only): $300 times 250$ px, JPG/PNG, max 2 MB

6. Text & Dynamic Ads (Spotlight & Follower Ads)

These cost-per-click (CPC) or cost-per-impression (CPM) right-rail ad units are exclusively visible on desktop versions of LinkedIn.

• Text Ads:
  • Logo Image: $100 times 100$ px (JPG/PNG, max 2 MB)
  • Headline: Up to 25 characters
  • Description: Up to 75 characters
• Spotlight Ads:
  • Company Logo: $100 times 100$ px (JPG/PNG, max 2 MB)
  • Background Image (Optional): $300 times 250$ px (JPG/PNG, max 2 MB)
  • Headline: Up to 50 characters
  • Description: Up to 70 characters
  • CTA Text: Up to 18 characters

Quick Optimization Checklist

1. Design for Mobile First: Over 60% of LinkedIn traffic originates on mobile devices. Prioritize square ($1:1$) or vertical ($4:5$) aspect ratios for feed placements to occupy maximum screen real estate.
2. Mind the Cutoffs: Keep critical text and logos away from the outer edges of images, and front-load your messaging inside the 150-character introductory text limit to avoid automatic truncation.