LinkedIn Ad Specs and Character Limits: The 2026 Complete Guide

LinkedIn ad specs are easy to overlook until they bite you. You design a beautiful image at 16:9, upload it, and LinkedIn crops it to a square. You write a punchy 90-character headline, submit it, and the campaign manager throws a validation error. Getting specs wrong before you start means rework — sometimes after the designer has already moved on to the next project. This guide puts everything in one place so you can brief creative correctly the first time.

Sponsored Content — Single Image Ad

Single image Sponsored Content is the most common LinkedIn ad format. It appears in the feed on both desktop and mobile, making it the highest-reach placement available on the platform.

Image specifications

• Recommended size: 1200 × 627 px (1.91:1 landscape ratio)
• Square option: 1200 × 1200 px — performs well on mobile feeds where square fills more screen real estate
• Accepted file types: JPG, PNG, GIF (static only — animated GIFs are not supported)
• Maximum file size: 5 MB
• Minimum width: 400 px (anything smaller will be rejected)

Character limits

CTA button options

LinkedIn provides a fixed set of CTA options — you can't write custom button text. Available options: Learn More, Download, Get Quote, Sign Up, Register, Subscribe, Apply Now, Request Demo, Try for Free, Contact Us, Join Now.

"Learn More" is the default recommendation for most campaigns — it's the lowest-friction option and consistently achieves higher CTR than action-specific CTAs for top-of-funnel audiences.

Sponsored Content — Carousel Ad

Carousel ads let you tell a story across multiple cards, showcase a product range, or break a complex message into digestible steps. They require more creative production but often deliver higher engagement than single-image ads.

• Number of cards: 2–10 cards per carousel
• Image size: 1080 × 1080 px (square only — landscape is not supported for carousel cards)
• File types: JPG, PNG
• Max file size per card: 10 MB
• Card headline: 45 characters maximum
• Intro text: 255 characters maximum (appears above all cards)
• Card destination URL: Each card can link to a different URL, making carousels useful for product category pages or multi-step journeys

Message Ads (InMail)

Message Ads are delivered directly to LinkedIn members' inboxes and only appear when the recipient is active on LinkedIn — which is why open rates are typically higher than email. The tradeoff is cost: Message Ads are priced per send, not per click.

Personalization tokens (%FIRSTNAME%, %COMPANY%) are available in the body and subject line. Using the recipient's first name in the subject line typically improves open rates, but overuse feels spammy — use it once, at the start.

Text Ads (Right Rail)

Text Ads appear in the right column on LinkedIn and are desktop-only — they don't show on mobile at all. They're the most cost-efficient format but have very low visibility compared to in-feed placements.

The 25-character headline limit is brutally tight — less than a tweet. Front-load the most important word. With only 25 characters, "Free CRM trial" (15 chars) beats "Try our award-winning CRM platform for free" every time.

Best practices for LinkedIn creative

• Use faces in images. Ads featuring people — especially faces looking directly at the camera — consistently outperform product-only or graphic-only images on LinkedIn. The platform's professional context makes human connection more compelling.
• Keep intro text under 100 characters. Anything beyond ~100 characters gets hidden behind a "see more" link on mobile. Your core message needs to land before that cutoff.
• Default to "Learn More" as your CTA. It's low-friction and works for nearly every offer type. More specific CTAs ("Download," "Apply Now") can improve quality of clicks but often reduce total CTR — use them when lead quality matters more than volume.
• Test square images. The 1200 × 1200 px square format takes up significantly more vertical space on mobile feeds than the 1.91:1 landscape format. For mobile-heavy audiences, square images often win on CTR.
• Avoid text-heavy images. LinkedIn doesn't enforce a text-on-image limit the way Facebook does, but text-heavy creative tends to underperform. Let the ad copy carry the message; use the image for visual impact.