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

When running paid campaigns on LinkedIn, getting your strategy right is only half the battle. If your creative assets don’t match LinkedIn’s rigid technical requirements, your ads will either look distorted, fail to upload entirely, or miss out on prime screen real estate. Because LinkedIn is the premier platform for B2B marketing, decision-makers scroll quickly through high-density professional feeds—meaning your specs, dimensions, and text lengths must be meticulously optimized.

This comprehensive guide breaks down the exact technical specifications and creative rules for every major LinkedIn ad format.

1. Single Image Ads (Sponsored Content)

Single image ads are the backbone of most LinkedIn campaigns. They appear directly in the user’s desktop and mobile feed, blending native posts with targeted messaging.

• File Types: JPG, PNG, or GIF
• Maximum File Size: 5 MB
• Aspect Ratios & Dimensions:
  • Landscape (Horizontal): 1.91:1 ratio | Recommended: 1200 x 628 pixels (Min: 640 x 360 px) — Delivers on both desktop and mobile.
  • Square: 1:1 ratio | Recommended: 1200 x 1200 pixels (Min: 360 x 360 px) — The gold-standard compromise for balanced display across all devices.
  • Vertical: 4:5 or 1:1.91 ratio | Recommended: 720 x 900 pixels (Min: 360 x 640 px) — Mobile-only; maximizes vertical feed footprint.
• Text Limits & Copy Specs:
  • Introductory Text: Up to 600 characters (Recommended: under 150 characters to avoid truncation with a “Read more” link).
  • Headline: Up to 200 characters (Recommended: ~70 characters).
  • Description (LinkedIn Audience Network only): Up to 300 characters (Recommended: ~70 characters).
  • Ad Name: Up to 255 characters (Optional, internal use only).

2. Video Ads

Video ads capture attention far longer than static images, making them ideal for product walkthroughs, customer case studies, and thought leadership snippets.

• File Format: MP4
• File Size Range: 75 KB to 500 MB (Up to 5 GB depending on upload tool)
• Duration: 3 seconds to 30 minutes (Best practice for performance: 15 to 30 seconds).
• Aspect Ratios & Resolutions:
  • Landscape (16:9): 1920 x 1080 px
  • Square (1:1): 1080 x 1080 px (Up to 1920 x 1920 px)
  • Vertical (4:5): 720 x 900 px or 1080 x 1350 px
  • Vertical (9:16): 720 x 1280 px up to 1080 x 1920 px
• Thumbnails: Optional custom thumbnail (JPG or PNG, max 2 MB, matching the video’s exact aspect ratio).
• Captions: Strongly recommended, as a vast majority of users browse LinkedIn with sound off.

3. Carousel Ads

Carousel ads allow you to showcase a sequence of 2 to 10 swipeable cards. They are exceptional for multi-step frameworks, product features, or sequential storytelling.

• Card Count: 2 to 10 cards
• File Types: JPG, PNG, or non-animated GIF
• Max File Size: 10 MB per card
• Image Specs: Exactly 1080 x 1080 pixels (1:1 square ratio required for all cards).
• Copy Specs:
  • Introductory Text: Up to 255 characters.
  • Card Headline: Up to 45 characters per card.
  • Destination URL: Required for each card (can be unique per card).

4. Document Ads

Document ads let you distribute content magnets—like industry reports, whitepapers, or slide decks—directly inside the LinkedIn feed without forcing users to navigate to an external landing page immediately.

• File Formats: PDF, DOC, DOCX, PPT, or PPTX
• Max File Size: 100 MB
• Page Limit: Up to 300 pages maximum (Shorter, 5-to-15 page visual summaries or guides typically perform best).
• Design Tip: Keep text large (18pt+) and clean, as users preview documents directly within the feed interface.

5. Conversation Ads & Message Ads

Sponsored messaging allows you to deliver personalized direct messages to targeted prospects’ LinkedIn inboxes.

• Message Text: Up to 1,500 characters (Message Ads) or up to 8,000 characters (Conversation Ads).
• Subject Line: Up to 60 characters.
• Call-to-Action (CTA) Button: Up to 20 characters.
• Optional Companion Banner (Desktop Only):
  • Dimensions: 300 x 250 pixels
  • File Types: JPG, PNG, or GIF
  • Max File Size: 2 MB

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

These classic right-rail units are budget-friendly options used primarily for desktop-heavy brand awareness and lead gen.

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

Quick-Check Summary for Campaign Builders

| Format | Core Dimension | Max File Size | Essential Creative Tip |
| :— | :— | :— | :— |
| Single Image | 1200 x 1200 px (Square) | 5 MB | Keep intro text under 150 chars to avoid “Read more” truncation. |
| Video | 1920 x 1080 px or 1080 x 1350 px | 500 MB – 5 GB | Always include captions; 80%+ watch muted. |
| Carousel | 1080 x 1080 px (1:1) | 10 MB per card | Hook viewers on Card 1 to encourage swiping. |
| Document | PDF, PPTX, DOCX | 100 MB | Use bold, legible typography for feed viewing. |

By adhering closely to these specifications, you ensure your creative assets render cleanly, pass automated review processes smoothly, and command maximum professional attention across LinkedIn’s ecosystem.