The Complete Guide to LinkedIn Paid Ad Specs

Running campaigns on LinkedIn without checking the technical requirements beforehand is a fast track to blurred imagery, truncated text, or rejected submissions. Because LinkedIn caters to a professional audience operating across desktop and mobile devices, its creative guardrails are precise.

1. Single Image Ads

Single image ads are the backbone of most LinkedIn campaigns. They appear directly in the user’s feed and support three main aspect ratios.

• Landscape (1.91:1):
  • Recommended Size: $1200 times 628$ pixels
  • Delivery: Both desktop and mobile
• Square (1:1):
  • Recommended Size: $1200 times 1200$ pixels
  • Delivery: Both desktop and mobile
• Vertical (4:5):
  • Recommended Size: $720 times 900$ pixels (or up to $1080 times 1350$ pixels)
  • Delivery: Mobile only (takes up valuable screen space)

General File Rules:

• Formats: JPG, PNG, or non-animated GIF
• Max File Size: 5 MB
• Copy Caps: Introductory text should stay under 150 characters (though up to 600 is technically allowed, text gets cut off), and headlines should stick to 70 characters.

2. Video Ads

Video is heavily favored for product demos, customer testimonials, and thought leadership. LinkedIn supports multiple framing choices.

• Aspect Ratios & Resolutions:
  • Landscape (16:9): $1920 times 1080$ px
  • Square (1:1): $1920 times 1920$ px max
  • Vertical (4:5): $720 times 900$ px recommended
  • Vertical (9:16): $1080 times 1920$ px max
• Technical Constraints:
  • File Format: MP4
  • File Size: 75 KB to 500 MB
  • Duration: 3 seconds to 30 minutes (though high-performing response ads generally hook viewers in the first 5 seconds).
  • Frame Rate: 30 FPS or lower

3. Carousel Ads

Carousels let you string together 2 to 10 swipeable cards, making them ideal for step-by-step guides, feature breakdowns, or product lines.

• Card Image Size: $1080 times 1080$ pixels (1:1 square ratio)
• File Formats: JPG or PNG
• Max File Size: 10 MB per card
• Copy Caps: Card headlines max out at 45 characters, and intro text allows up to 255 characters.

4. Document Ads

If you are gating a whitepaper, ebook, or ultimate guide, Document Ads allow users to flip through your PDF or presentation natively in-feed without leaving LinkedIn.

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

5. Conversation & Message Ads

Sent directly to a user’s LinkedIn Messaging inbox, these formats rely heavily on text length and personal touch rather than massive imagery.

• Message Text: Up to 1,500 characters (Message Ads) or up to 8,000 characters for branching paths (Conversation Ads)
• Call to Action (CTA): 20 characters max
• Optional Companion Banner: A $300 times 250$ pixel desktop-only visual (JPG or PNG, max 2 MB).

Quick Reference Table

| Format | Core Asset Dimension | Max File Size | Accepted File Types |
| :— | :— | :— | :— |
| Single Image | $1200 times 1200$ px (Square) | 5 MB | JPG, PNG, GIF |
| Video | $1920 times 1080$ px (16:9) / $1080 times 1920$ px (9:16) | 500 MB | MP4 |
| Carousel | $1080 times 1080$ px per card | 10 MB per card | JPG, PNG |
| Document | Standard document layout | 100 MB | PDF, PPTX, DOCX |
| Text Ads | $100 times 100$ px (Logo) | 2 MB | JPG, PNG |