The Ultimate Guide to LinkedIn Paid Ad Specs: Dimensions, Limits, and Creative Best Practices

When running B2B campaigns, hitting the right target audience is only half the battle. If your creative assets don’t fit LinkedIn’s strict technical guardrails, your ads can get rejected, look pixelated, or experience awkward cropping that tanks your click-through rates.

Whether you are launching a thought leadership campaign, driving lead gen form completions, or promoting a company event, mastering LinkedIn’s ad specifications is essential for professional media buying. This comprehensive guide breaks down the core technical dimensions, character limits, and file constraints for LinkedIn’s most popular paid ad formats.

1. Single Image Ads

Single image ads are the backbone of LinkedIn advertising, appearing directly in the user’s main feed. They are versatile, clean, and support multiple aspect ratios depending on your campaign goals.

• Aspect Ratios & Recommended Sizes:
  • Landscape (1.91:1): 1200 × 628 px (Great for general desktop and mobile reach)
  • Square (1:1): 1200 × 1200 px (High-impact balanced look)
  • Vertical (4:5): 720 × 900 px (Dominates mobile screens)
• File Types: JPG, PNG, or GIF (non-animated)
• Max File Size: 5 MB
• Copy Limits:
  • Introductory Text: Up to 150 characters recommended to avoid truncation (hard cap up to 3,000 characters).
  • Headline: 70 characters recommended (hard cap up to 200 characters).

2. Video Ads

Video is one of the strongest mediums for B2B storytelling, product walkthroughs, and executive branding. LinkedIn supports multiple orientations to fit how professionals consume content on the go.

• Aspect Ratios & Dimensions:
  • Landscape (16:9): 1920 × 1080 px
  • Square (1:1): 1080 × 1080 px
  • Vertical (4:5): 1080 × 1350 px (Recommended for mobile feeds)
  • Vertical (9:16): 1080 × 1920 px
• File Format: MP4
• File Size: 75 KB to 500 MB
• Duration: 3 seconds to 30 minutes (Though high-performing B2B videos usually focus on the 15-to-30-second sweet spot).
• Frame Rate & Audio: 30 FPS recommended; AAC audio.

3. Carousel Ads

Carousel ads let you showcase a sequence of 2 to 10 swipeable cards. They are ideal for step-by-step guides, multi-feature product rollouts, or telling a sequential brand story.

• Card Specifications:
  • Image Size: 1080 × 1080 px (1:1 square ratio)
  • Number of Cards: 2 to 10 cards
  • File Types: JPG or PNG
  • File Size: Max 10 MB per card
• Copy Limits:
  • Introductory Text: Up to 255 characters recommended.
  • Card Headline: Up to 45 characters.

4. Document Ads

Document ads allow users to read native PDFs, slide decks (PPT/PPTX), or whitepapers directly within the LinkedIn feed without navigating away to an external landing page. This format is a lead generation powerhouse for gated reports and eBooks.

• File Formats: PDF, DOC, DOCX, PPT, PPTX
• Max File Size: Up to 100 MB
• Page Limit: Up to 300 pages (though 5–15 pages typically yield higher engagement rates).
• Introductory Text: Up to 150 characters recommended to prevent early cutoff.

5. Message & Conversation Ads

Delivered straight into a professional’s LinkedIn Messaging inbox, Message and Conversation ads offer a personalized, direct-response approach. Conversation ads take it a step further by offering choose-your-own-path branching buttons.

• Sender Image: Pulls directly from the designated sender’s personal LinkedIn profile.
• Optional Desktop Banner: 300 × 250 px (JPG or PNG, max 2 MB).
• Copy Limits (Conversation Ads):
  • Message Text: Up to 8,000 characters.
  • Custom Footer/Disclaimer: Up to 20,000 characters.
  • Call-to-Action (CTA) Button: Up to 25 characters.

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

Found on the desktop right-rail, text and dynamic ads are cost-effective options for brand awareness, driving page followers, or promoting newsletters.

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

Pro-Tips for LinkedIn Ad Success

1. Design for Mobile First: Over 60% of LinkedIn traffic flows through mobile devices. Always prioritize square (1:1) or vertical (4:5) formats over traditional landscape styles to claim more visual real estate in the feed.
2. Front-Load Your Hook: Keep critical text within the first 150 characters of your intro copy so it doesn’t get masked behind a “…see more” truncation link.
3. Keep Lead Gen Forms Short: When pairing your ads with LinkedIn Lead Gen Forms, stick to 3 to 4 core fields (