The Complete Guide to LinkedIn Ad Sizes and Specs

Running ads on LinkedIn is one of the most powerful ways to reach decision-makers, industry experts, and B2B buyers. However, unlike consumer-heavy platforms where creative flexibility is wide open, LinkedIn is a professional ecosystem. If your creative assets are poorly formatted, awkwardly cropped, or violate technical limits, your campaigns risk looking amateurish—or worse, getting rejected outright.

Getting your dimensions right is the foundational step to maximizing click-through rates (CTR) and protecting your ad budget. Here is your comprehensive, up-to-date guide to LinkedIn ad sizes, formats, and best practices.

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1. Single Image Ads (Sponsored Content)

Single image ads appear directly in the user’s main LinkedIn feed. Because they blend with organic posts, they are your bread-and-butter format for brand awareness, lead generation, and content promotion.

LinkedIn gives you three primary aspect ratio choices depending on your design layout:

• Square (1:1):
  • Recommended Size: 1200 x 1200 pixels
  • Best For: Universal delivery across both desktop and mobile feeds. It takes up robust screen space without feeling intrusive.
• Landscape (1.91:1):
  • Recommended Size: 1200 x 628 pixels
  • Best For: Traditional horizontal imagery and desktop-heavy viewing.
• Vertical (4:5):
  • Recommended Size: 720 x 900 pixels
  • Best For: Mobile-only delivery. This format captures maximum real estate on smartphones, dramatically boosting visual engagement.

Technical Specifications:

• File Types: JPG, PNG, or GIF (non-animated)
• Max File Size: 5 MB
• Copy Limits: Intro text (up to 150 characters recommended for safety, though longer text truncates), Headline (up to 70 characters).

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2. Video Ads

B2B buyers love video content, but LinkedIn video requirements can be nuanced. Choosing the right aspect ratio ensures your message doesn’t get cut off.

• Landscape (16:9): 1920 x 1080 pixels (Classic widescreen format)
• Square (1:1): Up to 1920 x 1920 pixels
• Vertical (4:5 or 9:16):
  • 4:5: 720 x 900 pixels (Recommended vertical feed size)
  • 9:16: 720 x 1280 up to 1080 x 1920 pixels (Best for immersive mobile storytelling)

Technical Specifications:

• File Format: MP4
• File Size Range: 75 KB to 500 MB
• Duration: 3 seconds to 30 minutes (though high-performing B2B response ads typically hover between 15 and 30 seconds).

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3. Carousel Image Ads

Carousel ads let you showcase a sequence of 2 to 10 swipeable cards. They are phenomenal for step-by-step guides, product feature deep-dives, or breaking down complex data sets.

• Recommended Card Size: 1080 x 1080 pixels (1:1 aspect ratio)
• File Format: JPG or PNG
• Max File Size: Up to 10 MB per card
• Copy Limits: Card Headline (up to 45 characters), Intro text (up to 255 characters).

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4. Document Ads

If you want to gate or share high-value assets—like whitepapers, research reports, or slide decks—directly in the feed without forcing users to a landing page immediately, Document Ads are your go-to option.

• Accepted File Types: PDF, PPT, PPTX, DOC, DOCX
• Max File Size: 100 MB
• Page Limit: Up to 300 pages (though shorter, punchier assets generally convert better).

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5. Thought Leader Ads

A modern staple of LinkedIn advertising, Thought Leader Ads allow you to sponsor authentic organic posts written by employees or industry voices rather than just a brand handle.

• They inherit the exact same media specs (Single Image or Video) as the underlying organic post, meaning you simply align your creative briefs with standard feed dimensions.

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

These classic right-rail ads are budget-friendly and excel at desktop-focused lead acquisition, brand visibility, and driving company page follows.

• Text Ads (Right-Rail):
  • Logo Size: 100 x 100 pixels (JPG or PNG, max 2 MB)
  • Copy Limits: Headline (25 characters), Description (75 characters).
• Spotlight & Follower Ads:
  • Company Logo: 100 x 100 pixels
  • Optional Background Image (Spotlight only): 300 x 250 pixels
  • Copy Limits: Headline (up to 50 characters), Description (up to 70 characters), Custom CTA (up to 18 characters).

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7. Message & Conversation Ads

Delivered directly to a user’s LinkedIn Messaging (InMail) inbox, these ads foster one-on-one professional conversations.

• Desktop Banner Companion: Optional 300 x 250 pixels (JPG or PNG, max 2 MB). This banner displays on the right side of the desktop interface while the message is open.
• Copy Limits: Up to 8,000 characters for message text, with custom button text limits around 25 characters.

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Quick-Reference Summary Table

| Ad Format | Optimal Dimensions / Aspect Ratio | File Types | Max File Size |
| :— | :— | :— | :— |
| Single Image (Square) | 1200 x 1200 px (1:1) | JPG, PNG, GIF | 5 MB |
| Single Image (Landscape) | 1200 x 628 px (1.91:1) | JPG, PNG, GIF | 5 MB |
| Single Image (Vertical) | 720 x 900 px (4:5) | JPG, PNG, GIF | 5 MB |
| Video Ads | 16:9, 1:1, 4:5, or 9:16 | MP4 | 500 MB |
| Carousel Cards | 1080 x 1080 px (1:1) | JPG, PNG | 10 MB / card |
| Document Ads | N/A | PDF, DOCX, PPTX | 100 MB |
| Text / Dynamic Ads | 100 x 100 px (Logo) | JPG, PNG | 2 MB |
| Messaging Banners | 300 x 250 px | JPG, PNG | 2 MB |

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Pro-Tips for LinkedIn Ad Design Success

1. Design for Mobile First: Over 60% of LinkedIn traffic originates on mobile devices. Square (1:1) and vertical (4:5) sizes occupy significantly more screen space and routinely outperform old-school landscape layouts in click-through rates.
2. Watch the Safe Zones: Keep critical branding, text overlays, and key visuals centered. Avoid putting text near the very edges where UI elements (like video timers or profile icons) might overlap.
3. Keep Text Clean: While LinkedIn doesn’t strictly enforce archaic “20% text rules” anymore, cluttered visuals perform poorly in professional feeds. Let clear typography and strong contrast do the talking.