Mastering LinkedIn Paid Ad Specs: The Definitive Creative Guide

When running B2B campaigns, getting your targeting right is only half the battle. If your creative assets are cropped awkwardly, rendered blurry on mobile, or rejected by LinkedIn’s ad review system due to a file size miscalculation, your ad spend stalls before it even starts.

Navigating LinkedIn’s technical requirements doesn’t have to be a guessing game. This guide breaks down the precise dimensions, file limits, and text boundaries for LinkedIn’s primary ad formats so your campaigns look polished, professional, and built to convert.

1. Single Image Ads (Sponsored Content)

Single image ads remain a staple for B2B marketers. Because users browse LinkedIn across desktop and mobile, choosing the right aspect ratio heavily dictates how much screen estate your ad commands.

• Landscape (1.91:1):
  • Recommended Size: $1200 times 628$ pixels (Min. $640 times 360$, Max. $7680 times 4320$)
  • Best for: Universal delivery across desktop and mobile feeds.
• Square (1:1):
  • Recommended Size: $1200 times 1200$ pixels (Max. $4320 times 4320$)
  • Best for: Balanced visual weight on both desktop and mobile.
• Vertical (4:5):
  • Recommended Size: $720 times 900$ pixels (Mobile only)
  • Best for: Maximizing thumb-stop power on mobile devices.
• Technical Limits: JPG, PNG, or GIF format; maximum file size of 5 MB.
• Copy Caps: Introductory text under 150 characters (truncates around this mark, though up to 600 is allowed); Headline recommended around 70 characters (up to 200 max).

2. Video Ads

Video is one of the most effective ways to build brand affinity and convey complex solutions, but LinkedIn has strict encoding guidelines.

• Aspect Ratios & Resolutions:
  • Landscape (16:9): $1920 times 1080$ pixels max
  • Square (1:1): Up to $1920 times 1920$ pixels max
  • Vertical (4:5): $720 times 900$ pixels recommended (up to $1080 times 1350$)
  • Full Portrait (9:16): Up to $1080 times 1920$ pixels
• Technical Limits:
  • File format: MP4 (H.264 or VP8 codec).
  • File size: 75 KB to 500 MB.
  • Duration: 3 seconds to 30 minutes (though 15–30 seconds is the golden window for peak engagement).
  • Frame rate: 30 FPS or lower.
• Pro-Tip: Videos auto-play silently in the feed. Always burn open captions/subtitles directly into the video file and upload a custom thumbnail (JPG/PNG, max 2 MB matching your video’s aspect ratio).

3. Carousel Ads

Carousels let you tell a sequential story, showcase a product feature set, or break down step-by-step strategies.

• Card Specifications:
  • Card count: 2 to 10 cards.
  • Recommended resolution: $1080 times 1080$ pixels (1:1 square).
  • File format: JPG or PNG (non-animated).
  • Max file size: 10 MB per card.
• Copy Caps: Card headlines are strictly capped around 45 characters for sponsored carousels, while introductory text can reach up to 255 characters.

4. Document Ads

If you are gating a high-value whitepaper, research report, or ebook, Document Ads allow users to preview and swipe through PDFs directly inside their LinkedIn feed without forcing an immediate click-away.

• File Formats: PDF, DOC/DOCX, or PPT/PPTX.
• File Size & Length: Maximum file size of 100 MB; up to 300 pages (though shorter teaser versions typically convert better).

5. Message Ads & Conversation Ads

Directly dropping a tailored message into a prospect’s LinkedIn inbox yields high response rates when personalized thoughtfully.

• Message Ads: Text length up to 1,500 characters with a 20-character CTA button limit. Optionally pair it with a desktop companion banner.
• Conversation Ads: Allows branching “choose-your-own-path” messaging with up to 5 distinct CTAs and up to 8,000 characters of total content flow.
• Companion Banner Specs (Desktop Only): Exactly $300 times 250$ pixels, JPG or PNG, max 2 MB.

6. Text Ads & Spotlight Ads (Right-Rail)

These desktop-heavy formats are cost-effective options for steady brand awareness and lead generation.

• Text Ads:
  • Logo image: $100 times 100$ pixels (JPG/PNG, max 2 MB).
  • Copy: Headline up to 25 characters; Description up to 75 characters.
• Spotlight Ads:
  • Logo image: $100 times 100$ pixels (JPG/PNG, max 2 MB).
  • Optional custom background image: $300 times 250$ pixels (max 2 MB).
  • Copy: Headline up to 50 characters; Description up to 70 characters.

💡 Quick Checklist Before Launch:
Always double-check your landing page URLs, ensure mobile previews look legible before publishing, and verify that your text overlays stay comfortably away from corners where LinkedIn overlays buttons or timestamps.