The Ultimate Guide to LinkedIn Ad Sizes and Specifications

Running a B2B marketing campaign without knowing your ad dimensions is like trying to fit a square peg into a round slot—except instead of a toy, you’re burning actual ad budget. LinkedIn is the premier network for professional networking, lead generation, and B2B account-based marketing. However, its layout constraints are strict. If your image aspect ratio is off by a pixel, or your text exceeds character thresholds, LinkedIn will crop, truncate, or reject your creative entirely.

This comprehensive guide breaks down the exact sizes, technical dimensions, and copywriting limits for every major LinkedIn ad format, ensuring your campaigns look sharp, professional, and built to convert.

1. Single Image Ads (Sponsored Content)

Single image ads live natively in the LinkedIn feed. Because professionals scroll quickly on both desktop and mobile, choosing the right aspect ratio dictates how much screen estate your brand commands.

| Orientation | Recommended Resolution | Aspect Ratio | Max File Size & Formats |
| :— | :— | :— | :— |
| Landscape | $1200 times 628$ px | 1.91:1 | 5 MB max (JPG, PNG, GIF) |
| Square | $1200 times 1200$ px | 1:1 | 5 MB max (JPG, PNG, GIF) |
| Vertical | $720 times 900$ px | 4:5 | 5 MB max (JPG, PNG, GIF) |

• Intro Text: Up to 150 characters recommended to avoid truncation (hard limit at 3,000 characters).
• Headline: Up to 70 characters before truncation (200 max).
• Pro Tip: Square ($1200 times 1200$) and vertical ($720 times 900$) formats yield significantly higher mobile screen dominance than traditional landscape banners.

2. Carousel Ads

Carousel ads allow you to showcase a swipeable sequence of 2 to 10 cards, making them ideal for product breakdowns, step-by-step frameworks, or brand storytelling.

• Card Image Size: $1080 times 1080$ px recommended.
• Aspect Ratio: 1:1 square mandatory for all cards.
• Max File Size: 10 MB per card (JPG, PNG, or non-animated GIF).
• Card Headline: Up to 45 characters (text wraps across two lines before cutting off).
• Intro Text: Up to 150 characters safely displayed (255 max).

3. Video Ads

Video is a heavy hitter for B2B tech and service demos. LinkedIn supports multiple orientations depending on whether your video is optimized for a cinematic desktop view or vertical mobile consumption.

• Landscape (16:9): $1920 times 1080$ px
• Square (1:1): Up to $1920 times 1920$ px
• Vertical (4:5): $720 times 900$ px recommended
• Vertical (9:16): $720 times 1280$ to $1080 times 1920$ px
• Technical Constraints: MP4 format, file size ranging from 75 KB to 500 MB, duration from 3 seconds up to 30 minutes (though 15–30 seconds yields the highest completion rates). Always upload a matching custom thumbnail (JPG/PNG, max 2 MB).

4. Document Ads

Document ads allow users to read whitepapers, research reports, or slide decks directly inside the LinkedIn feed without navigating to a landing page.

• Supported File Types: PDF, DOC, DOCX, PPT, PPTX.
• Max File Size: Up to 100 MB.
• Page Limit: Up to 300 pages (or 1 million words).
• Intro Text & Headline: Same limits as single-image ads (150 chars intro text, 70 chars headline before truncation).

5. Thought Leader Ads

Thought Leader Ads amplify organic posts made by executives, employees, or creators rather than corporate pages.

• The Catch: You don’t upload a raw creative asset directly into the ad builder; instead, you sponsor an already published post from a user who has granted you advertiser permissions.
• Specs: Follow whatever image, video, or text specifications the original native post utilizes.

6. Message & Conversation Ads

Delivered straight into a target user’s LinkedIn Messaging (InMail) inbox, these ads secure high open rates when personalized properly.

• Sender Image: Automatically pulled from the designated sender’s personal LinkedIn profile.
• Optional Desktop Banner: $300 times 250$ px (JPG, PNG, or non-animated GIF, max 2 MB). Note: Only visible on desktop screens.
• Subject Line: Up to 60 characters.
• Message Body Text: Up to 1,500 characters for Message Ads; up to 8,000 characters for complex Conversation Ads.
• Call-to-Action (CTA) Button: Up to 25 characters.

7. Follower, Spotlight, and Text Ads

These smaller, performance-driven units live on the right-hand rail of the desktop interface.

• Text Ads: Utilize a mandatory $100 times 100$ px company logo (JPG/PNG, max 2 MB), a headline capped at 25 characters, and a description capped at 75 characters.
• Spotlight Ads: Feature a $100 times 100$ px logo, an optional $300 times 250$ px background image, a headline (up to 50 characters), and a description (up to 70 characters).

Summary Checklist for Designers

Before shipping your assets to your media buyer, verify these rules of thumb:

1. Design for Mobile First: Over 60% of LinkedIn traffic is mobile. Square ($1:1$) and vertical ($4:5$) images dominate feed views.
2. Keep Core Text Centered: Avoid placing crucial text or logos near the bottom-right corner of video ads, where length overlays appear.
3. Double-Check Character Counts: Keep hook lines under 150 characters to prevent unwanted “See more” text folding.