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

When running B2B campaigns, hitting the exact technical specifications required by a platform can mean the difference between a high-performing lead generation engine and a rejected asset. LinkedIn has rigorous parameters for creative files, aspect ratios, and character counts. If your image is a few pixels off or your text exceeds truncation limits, your ad delivery can stall or look unprofessional.

This comprehensive guide breaks down the technical blueprints for every major LinkedIn ad format, ensuring your next campaign is built to spec.

1. Sponsored Content (Single Image Ads)

Single image ads appear directly in the LinkedIn feed alongside organic updates. They are versatile, easy to test, and support multiple aspect ratios depending on whether you want broad reach or maximum screen dominance.

• Aspect Ratios & Resolutions:
  • Landscape (1.91:1): 1200 × 628 pixels recommended (Desktop & Mobile)
  • Square (1:1): 1200 × 1200 pixels recommended (Desktop & Mobile)
  • Vertical (4:5): 720 × 900 pixels recommended (Mobile only)
• File Types: JPG, PNG, or non-animated GIF
• Max File Size: 5 MB
• Text Limits:
  • Introductory Text: Up to 150 characters before mobile truncation (3,000 max)
  • Headline: Up to 70 characters before truncation (200 max)

2. Video Ads

LinkedIn video ads drive high engagement by capturing attention in the feed. Because many users browse with sound off, burned-in or uploaded SRT captions are non-negotiable.

• Aspect Ratios & Resolutions:
  • Landscape (16:9): 1920 × 1080 pixels (min 640 × 360)
  • Square (1:1): 1920 × 1920 pixels (min 360 × 360)
  • Vertical (4:5): 1080 × 1350 pixels (min 360 × 450)
  • Vertical (9:16): 1080 × 1920 pixels (min 360 × 640)
• File Format & Size: MP4 format; file size between 75 KB and 500 MB
• Duration: 3 seconds to 30 minutes (perform best when kept between 15–30 seconds)
• Captions: Separate SRT file upload required (recommended for accessibility and sound-off viewing)
• Text Limits: Same as single image ads (Introductory text: 150 chars optimal; Headline: 70 chars optimal)

3. Carousel Ads

Carousels allow you to tell a sequential story, showcase a product suite, or present a step-by-step framework using swipeable cards.

• Cards: 2 to 10 cards per ad
• Card Image Spec: 1080 × 1080 pixels (1:1 aspect ratio)
• Max File Size: 10 MB per card
• File Types: JPG, PNG, or non-animated GIF
• Text Limits:
  • Introductory Text: Up to 150 characters before truncation (255 max)
  • Card Headline: Up to 45 characters (two lines max before truncation)

4. Document Ads

Document ads enable users to read and download whitepapers, case studies, or reports natively within the LinkedIn feed without navigating away to a landing page.

• File Types: PDF, DOC, DOCX, PPT, or PPTX
• Max File Size: Up to 100 MB
• Page Limit: Up to 300 pages (recommended under 10 pages for optimal lead-magnet conversion)
• Aspect Ratios: Vertical, horizontal, or square layouts supported
• Text Limits: Introductory text up to 150 characters (600 max); Headline up to 70 characters

5. Sponsored Messaging (Message Ads & Conversation Ads)

Direct messaging ads land straight into a professional’s LinkedIn InMail inbox, bypassing the feed entirely.

• Message Ads:
  • Subject Line: Up to 60 characters
  • Message Body: Up to 1,500 characters (supports up to 3 links and 10 emojis)
  • CTA Button: Up to 20 characters
  • Optional Companion Banner: 300 × 250 pixels (JPG, PNG, or GIF, max 2 MB)
• Conversation Ads:
  • Intro Message: Up to 8,000 characters
  • Branching Paths: Up to 5 CTA buttons per message layer (25-character limit per button)
  • Optional Companion Banner: 300 × 250 pixels

6. Text Ads & Dynamic Ads

Text ads and dynamic personalization ads (such as Follower or Spotlight ads) live primarily on the desktop right rail, offering a lightweight, cost-effective way to drive steady brand awareness.

• Text Ads (Desktop Only):
  • Image: 100 × 100 pixels (JPG or PNG, max 2 MB)
  • Headline: Up to 25 characters
  • Description: Up to 75 characters
• Spotlight & Follower Ads:
  • Company Logo: 100 × 100 pixels minimum
  • Headline: Up to 50 characters
  • Description: Up to 70 characters
  • Custom Background Image (Spotlight only): Exactly 300 × 250 pixels (max 2 MB)

Quick Checklist Before You Launch

1. Watch the Truncation Zones: Keep your primary value proposition and hook inside the first 150 characters of introductory text so it doesn’t get hidden behind a “…see more” link.
2. Compress Intelligently: Ensure image file sizes comfortably sit below LinkedIn’s caps (5 MB for images, 2 MB for banners/logos) while saving files in the sRGB color profile to prevent color dullness.
3. Double-Check Destination URLs: Always verify that your tracking parameters (UTMs) are appended correctly and that URLs begin with https://.