Mastering LinkedIn Ad Sizes: The Ultimate Guide for High-Performing Campaigns

In the world of B2B marketing, LinkedIn is the undisputed heavyweight champion. With over a billion professionals networking, sharing industry insights, and searching for solutions, it is a goldmine for lead generation and brand awareness.

However, running a successful campaign takes more than just a great hook and a targeted audience. If your creative assets are blurry, awkwardly cropped, or cut off mid-sentence, your target audience will scroll right past. Ad specs matter.

To help you maximize your return on ad spend (ROAS) and ensure your brand looks polished and professional, let’s dive into the complete, up-to-date guide for LinkedIn ad sizes and formats.

Why LinkedIn Ad Sizes Matter

First impressions happen in milliseconds. On a crowded feed, a well-optimized image or video grabs attention instantly, signaling that your brand is trustworthy and detail-oriented. Using the correct dimensions also prevents LinkedIn’s platform from automatically compressing or cropping your creative in unflattering ways.

1. Single Image Ads

Single image ads are the bread and butter of LinkedIn advertising. They appear directly in the user’s feed and are versatile enough for brand awareness, event promotion, or driving traffic to a landing page.

• Landscape (Horizontal)
  • Recommended Size: 1200 x 627 pixels
  • Aspect Ratio: 1.91:1
  • Best For: Traditional website banners and desktop-heavy viewports.
• Square
  • Recommended Size: 1080 x 1080 pixels
  • Aspect Ratio: 1:1
  • Best For: Balanced visual storytelling that looks equally great on mobile and desktop feeds.
• Vertical
  • Recommended Size: 1080 x 1350 pixels (or 600 x 900 pixels minimum)
  • Aspect Ratio: 4:5 or 2:3
  • Best For: Mobile-first campaigns. Vertical ads take up more screen real estate as users scroll, dramatically boosting engagement rates.

2. Carousel Image Ads

Carousels allow you to showcase multiple images or swipeable cards in a single ad unit. They are fantastic for telling a step-by-step story, highlighting multiple product features, or breaking down complex data.

• Recommended Size: 1080 x 1080 pixels per card
• Aspect Ratio: 1:1
• Number of Cards: 2 to 10 cards per carousel
• File Formats: JPG, PNG (non-animated)
• Max File Size: 10 MB per card

3. Video Ads

Video is one of the most engaging mediums on LinkedIn. Whether you’re sharing customer testimonials, product walkthroughs, or thought-leadership clips, getting the aspect ratio right is critical.

• Landscape Video
  • Resolution: 1280 x 720 (16:9 aspect ratio)
  • Length: 3 seconds to 30 minutes (though 15–30 seconds typically performs best for retention)
• Square Video
  • Resolution: 1080 x 1080 (1:1 aspect ratio)
• Vertical Video
  • Resolution: 1080 x 1350 or 1080 x 1920 (9:16 aspect ratio)
  • Best For: Capturing mobile scrollers with immersive, full-screen vertical content.
• Max File Size: 200 MB

4. Thought Leader Ads

Thought Leader Ads allow you to amplify posts written by real people—such as your company executives, employees, or industry influencers—rather than just a faceless brand page.

Because these leverage native posts, they utilize the standard sizing guidelines of whatever media format the creator used (Single Image specs or Video specs), but they offer unprecedented authenticity and often drive significantly higher click-through rates (CTR).

5. Message Ads & Conversation Ads

Sent directly to a user’s LinkedIn Messaging (InMail) inbox, these ads allow for personalized, conversational engagement. While they don’t rely on image banners in the same way feed ads do, they do require a supporting asset:

• Custom Banner Image (Optional): 300 x 250 pixels (displayed on the desktop sidebar while users view the message).

6. Text Ads

Text ads are the budget-friendly, minimalist option that appear on the desktop sidebar of LinkedIn. They require a small square image alongside concise copy.

• Image Size: 100 x 100 pixels
• Aspect Ratio: 1:1
• Max File Size: 2 MB
• Copy Limits: Headline (up to 25 characters), Description (up to 75 characters).

Quick Best Practices for Success

1. Design for Mobile First: Over 60% of LinkedIn traffic originates from mobile devices. Vertical (4:5) and square (1:1) formats occupy more screen space and generally outperform horizontal layouts in the mobile feed.
2. Keep Text Out of the Lower Right Corner: On video ads, LinkedIn places time stamps and duration icons in the bottom-right corner. Keep important text and logos away from this zone.
3. Prioritize High-Contrast Design: Use colors that pop against LinkedIn’s clean white and light-gray interface, but maintain a professional aesthetic suitable for a B2B audience.
4. Test and Iterate: Don’t settle for your first design. Run A/B tests pitting a square image against a vertical image to see which format resonates best with your specific buyer persona.

By adhering to these dimensions and design principles, you’ll ensure your brand looks sharp, commands attention, and drives the pipeline results your business deserves.