The Complete Guide to LinkedIn Ad Sizes and Specs

Running a campaign on LinkedIn is unlike advertising on any other major platform. While platforms like Meta or TikTok lean heavily toward broad consumer appeal, LinkedIn is where decision-makers, enterprise buyers, and global professionals log in with a business-first mindset.

However, even the sharpest B2B copy and most precise targeting will underperform if your creative assets are poorly formatted, awkwardly cropped, or blurred by compression. Getting the technical dimensions right is the non-negotiable first step to protecting your ad budget.

This complete reference guide breaks down the essential LinkedIn ad sizes, format specifications, and text limits across all major campaign types.

1. Single Image Ads (Sponsored Content)

Single image ads are the backbone of LinkedIn advertising. They appear directly in the user’s feed, making versatility across desktop and mobile critical.

• Landscape (1.91:1):
  • Recommended Size: $1200 times 628$ pixels
  • Notes: Works across both desktop and mobile feeds. A classic, reliable layout, though it commands less vertical screen space.
• Square (1:1):
  • Recommended Size: $1200 times 1200$ pixels
  • Notes: Highly versatile, taking up more visual footprint than landscape on both mobile and desktop.
• Vertical (4:5):
  • Recommended Size: $720 times 900$ pixels
  • Notes: Mobile-only display. This format captures maximum attention as users scroll through their feeds on phones.
• Technical Limits: File formats accepted include JPG, PNG, and non-animated GIF, with a maximum file size of 5 MB.

2. Carousel Ads

Carousels let you tell a sequential story, showcase a product suite, or present a step-by-step breakdown using multiple swipeable cards.

• Card Dimensions: $1080 times 1080$ pixels ($1:1$ ratio recommended)
• Card Count: 2 to 10 cards per ad
• File Limits: Up to 10 MB per card (JPG, PNG, or static GIF)
• Text Constraints:
  • Introductory text: 255 characters max
  • Card headline: 45 characters max (keep it concise to prevent awkward truncation)

Pro Tip: Always maintain the exact same aspect ratio across every card in a single carousel. Mixing ratios causes LinkedIn to awkwardly re-frame your layout.

3. Video Ads

B2B buyers consume an immense amount of video content on LinkedIn. Choosing the right aspect ratio depends on whether your footage was designed for cinematic wide-screens or fast-paced mobile viewing.

| Aspect Ratio | Recommended Production Size | Best Used For |
| :— | :— | :— |
| 16:9 (Landscape) | $1920 times 1080$ px | Cross-platform repurposing, webinar clips, case studies |
| 1:1 (Square) | $1920 times 1920$ px max | Balanced feed presence on desktop and mobile |
| 4:5 (Vertical) | $720 times 900$ px (or up to $1080 times 1350$) | Optimal vertical real estate for mobile feeds |
| 9:16 (Vertical) | $1080 times 1920$ px | Immersive vertical full-screen experiences |

• Technical Limits: MP4 format; file size ranges from 75 KB up to 500 MB; duration can span anywhere from 3 seconds to 30 minutes (though high-converting B2B ads usually punch under the 30-second mark).

4. Document Ads (Thought Leadership & Lead Gen)

Document ads allow you to upload native PDFs, PowerPoint presentations ($PPT/PPTX$), or Word docs directly into the feed, letting users flip through slides or whitepapers without leaving LinkedIn.

• Aspect Ratios: Square ($1080 times 1080$ px) or Portrait ($1080 times 1350$ px) work best.
• File Requirements: PDF format is strongly recommended. Maximum file size is 100 MB, supporting up to 300 pages.

5. Text & Dynamic Ads (Right-Rail Formats)

Found on the desktop right-rail sidebar, these automated units rely heavily on concise copywriting and clean brand assets.

• Text Ads:
  • Logo size: $100 times 100$ pixels (JPG or PNG, max 2 MB)
  • Copy limits: Headline max 25 characters; Description max 75 characters.
• Spotlight Ads & Follower Ads:
  • Logo size: $100 times 100$ pixels
  • Optional Background Image (Spotlight only): $300 times 250$ pixels
  • Copy limits: Headline max 50 characters; Description max 70 characters.

Quick-Check Copy Limits Summary

When designing creative assets, remember that visual space and text boxes work hand-in-hand. Keep these overall character limits handy during drafting:

• Single Image Intro Text: 150 characters (recommended before “see more” truncation)
• Single Image Headline: 70 characters
• Carousel Card Headline: 45 characters
• Conversation / Message Ad CTA: 25 characters

Final Quality Checklist

Before launching your campaign, run through this final sanity check:

1. Are your files compressed? Keep images comfortably under the maximum file limit to ensure lightning-fast load times on mobile connections.
2. Did you respect safe zones? Keep vital typography, text, and logos away from the extreme edges of your templates to prevent cropping from UI overlays.
3. Is it readable on mobile? Over 60% of LinkedIn traffic happens on mobile devices. Preview your exports on an actual phone screen before pushing them live.