Mastering LinkedIn Paid Ad Specs: The Ultimate Blueprint for B2B Marketers

Running campaigns on LinkedIn can unlock decision-makers, enterprise leads, and high-value B2B pipeline opportunities that other social channels simply cannot reach. However, even the most compelling copy and sophisticated targeting will fall flat if your creative asset gets rejected by Campaign Manager or rendered awkwardly on a mobile screen.

Technical precision is everything. To protect your budget and maximize visual impact, you need to align your design and copywriting frameworks with LinkedIn’s strict structural requirements.

1. Single Image Ads

Single image ads remain the backbone of LinkedIn advertising, delivering flexibility across brand awareness, website traffic, and lead generation campaigns.

• Aspect Ratios & Dimensions:
  • Landscape (1.91:1): 1200 × 627 px recommended (min. 640 × 360 px)
  • Square (1:1): 1200 × 1200 px recommended (min. 360 × 360 px). Pro-tip: Square formatting commands significantly more visual real estate on mobile feeds than landscape.
  • Vertical (4:5): 720 × 900 px or 1200 × 1500 px (mobile-only delivery)
• File Types: JPG, PNG, or static GIF
• Max File Size: 5 MB
• Text Limits:
  • Introductory text: Up to 600 characters (first ~150 characters visible before truncation)
  • Headline: Up to 200 characters (first ~70 characters visible)

2. Video Ads

Video is unmatched for demonstrating complex software solutions, showcasing customer success stories, or driving top-of-funnel engagement.

• Aspect Ratios & Recommended Sizes:
  • Landscape (16:9): 1920 × 1080 px
  • Square (1:1): 1080 × 1080 px
  • Vertical (4:5 or 9:16): 720 × 900 px or 1080 × 1920 px
• File Format & Size: MP4 format; file size between 75 KB and 500 MB.
• Duration: 3 seconds to 30 minutes (though 15 to 30 seconds yields optimal retention).
• Text Limits: Same text parameters as single image ads (600 characters for intro text; 200 characters for headline).
• Critical Rule: Always embed open captions or closed-caption files. The vast majority of users browse LinkedIn on mobile with autoplay audio muted by default.

3. Carousel Ads

Carousels excel at sequential storytelling, product feature breakdowns, step-by-step guides, or multi-stat proof points.

• Card Count: 2 to 10 cards per ad.
• Card Dimensions: 1080 × 1080 px (1:1 square ratio required).
• File Format & Size: JPG or PNG (non-animated GIFs only); max 10 MB per card.
• Text Limits:
  • Introductory text: Up to 255 characters (Note: This is strictly shorter than standard single-image formats).
  • Card Headline: Up to 45 characters per card.

4. Document Ads

If you want to gate comprehensive whitepapers, annual industry benchmarks, or playbooks directly inside the feed without requiring an external landing page jump, Document Ads are your go-to format.

• File Types: PDF, DOC, DOCX, PPT, or PPTX.
• File Size & Page Limits: Up to 100 MB and a hard maximum of 300 pages (though 5–10 pages performs best for in-feed consumption).
• Text Limits: Introductory text ~150 recommended characters (up to 600); headline up to 70 recommended characters.
• Design Tip: Scale your font sizes up (at least 18pt) and structure layouts like presentation slides so text remains completely legible when scaled down on mobile viewports.

5. Message & Conversation Ads

Delivered straight into a prospect’s LinkedIn Messaging inbox, these formats bypass the cluttered feed entirely for a direct, 1-to-1 conversation feel.

• Message Body Text: Up to 8,000 characters (Conversation Ads allow branching paths and up to 5 custom Call-to-Action buttons).
• Optional Desktop Banner: 300 × 250 px (JPG or PNG, max 2 MB).
• Sender Profile: Must be sent via a designated verified employee profile within your organization.

6. Dynamic & Text Ads

Dynamic Ads (Spotlight and Follower ads) automatically customize themselves using the target user’s profile data (like their name, job title, or company logo) to drive engagement.

• Text Ads (Right-rail desktop placement):
  • Logo/Image: 100 × 100 px (JPG or PNG, max 2 MB).
  • Headline: Up to 25 characters.
  • Description: Up to 75 characters.
• Spotlight Ads:
  • Logo: 100 × 100 px.
  • Optional Background Image: 300 × 250 px (max 2 MB).
  • Headline: Up to 50 characters; Description up to 70 characters.

Summary Checklist for Campaign Success

Before hitting launch in LinkedIn Campaign Manager, run through this quick quality-assurance checklist:

1. Check your orientations: Are your square (1:1) or vertical (4:5) assets optimized for mobile users who dominate LinkedIn traffic?
2. Monitor safe zones: Keep key text, logos, and value props centered away from video timestamps or UI overlay corners.
3. Double-check text truncation: Ensure your core value proposition appears within the first 150 characters of your intro copy so it doesn’t get cut off before the “see more” link.