Reddit Ad Specs: Complete Format & Size Guide 2026

Getting your Reddit ad specs right is essential for campaign success. Improperly sized creative gets cropped, distorted, or rejected—wasting time and hurting performance. This guide covers every Reddit ad format's dimensions, file requirements, and character limits for 2026.

Bookmark this page as your quick reference for all Reddit advertising specifications.

Reddit Ad Formats Overview

Reddit offers several ad formats, each with specific creative requirements:

Ad Format	Best For	Key Specs Summary
Image Ads	Static promotional content	1080×1080 to 1920×1080, max 3MB
Video Ads	Engaging storytelling	Up to 15 min, max 1GB, 30 FPS
Carousel Ads	Multi-product/feature showcase	2-6 cards, same image specs
Conversation Ads	Native thread placement	Appears in comment sections
Takeover Ads	Premium brand awareness	Custom specs, contact Reddit

Image Ad Specs

Image ads are the most common Reddit ad format. Here are the complete specifications:

Image Dimensions

Reddit supports multiple aspect ratios for image ads:

Aspect Ratio	Dimensions	Best Use
1:1 (Square)	1080 × 1080 px	Mobile-first campaigns
4:5 (Portrait)	1080 × 1350 px	Mobile feed visibility
4:3 (Landscape)	1440 × 1080 px	Desktop-friendly content
16:9 (Widescreen)	1920 × 1080 px	Cinematic visuals

Recommended: 4:5 portrait or 1:1 square ratios perform best on mobile, where 70%+ of Reddit usage occurs.

Image File Requirements

Specification	Requirement
File Types	JPG, PNG
Maximum File Size	3 MB
GIF Support	Accepted but converted to static image
Minimum Resolution	300 × 300 px
Color Space	sRGB recommended

Image Ad Text Requirements

Element	Character Limit	Notes
Headline (Feed)	150 characters max	Displays in user feeds
Headline (Conversation)	100 characters max	For conversation placement
Body Text	Optional, varies by placement	Keep concise
Display URL	Automatically generated	From destination URL

Best practice: Keep headlines under 100 characters to ensure full visibility across all placements.

Video Ad Specs

Video ads on Reddit are highly engaging and support a range of formats:

Video Dimensions

Aspect Ratio	Dimensions	Best Use
1:1 (Square)	1080 × 1080 px	Balanced mobile/desktop
4:5 (Portrait)	1080 × 1350 px	Best for mobile (recommended)
4:3 (Landscape)	1440 × 1080 px	Desktop viewing
16:9 (Widescreen)	1920 × 1080 px	Cinematic content

Video File Requirements

Specification	Requirement
File Types	MP4, MOV
Maximum File Size	1 GB
Recommended File Size	Under 512 MB for optimal upload
Frame Rate	30 FPS
Video Codec	H.264 recommended
Audio Codec	AAC, 128 kbps+

Video Duration

Duration Type	Specification
Minimum	No strict minimum
Recommended	5–30 seconds
Optimal Length	60 seconds for engagement
Maximum	Up to 15 minutes

Best practice: Front-load your key message in the first 3 seconds. Most users scroll quickly, so hook attention immediately.

Video Thumbnail Specs

Specification	Requirement
Dimensions	400 × 300 px
Aspect Ratio	4:3 landscape
File Types	JPG, PNG
Maximum File Size	500 KB

Thumbnails display before autoplay and when users have autoplay disabled. Always upload a custom thumbnail rather than relying on auto-generated frames.

Video Ad Text Requirements

Element	Character Limit
Headline (Feed)	150 characters max
Headline (Conversation)	100 characters max
Call-to-Action	Pre-set options available

Carousel Ad Specs

Carousel ads let you showcase multiple images in a swipeable format:

Carousel Structure

Specification	Requirement
Minimum Cards	2
Maximum Cards	6
Card Uniformity	All cards must use same aspect ratio

Carousel Image Specs (Per Card)

Specification	Requirement
Dimensions	Same as image ads (1080×1080, 1080×1350, etc.)
File Types	JPG, PNG
Maximum File Size	3 MB per card
Aspect Ratio	Consistent across all cards

Carousel Text Requirements

Element	Character Limit	Notes
Ad Headline	150 characters	Applies to entire carousel
Card Headlines	Optional	Individual card text
Card Descriptions	Optional	Individual card text

Best practice: Use carousel ads to tell a sequential story, showcase product features, or display multiple products. Maintain visual consistency across all cards.

Conversation Ad Specs

Conversation ads appear within comment threads, providing native placement:

Conversation Ad Requirements

Specification	Requirement
Placement	Within comment sections
Headline Limit	100 characters (shorter than feed ads)
Image/Video	Same specs as standard ads
Engagement	Users can upvote, downvote, and comment

Conversation Ad Best Practices

• Shorter headlines required: 100 characters max (vs. 150 for feed)
• Native tone: Content should feel like part of the discussion
• Enable comments strategically: Be prepared to engage with responses
• Educational content wins: Users in threads expect helpful information

Conversation ads work exceptionally well when your content genuinely adds value to the discussion topic.

Text & Headline Requirements

Across all ad formats, these text specifications apply:

Character Limits Summary

Element	Feed Placement	Conversation Placement
Headline	150 characters	100 characters
Display URL	Auto-generated	Auto-generated
CTA Button	Pre-set options	Pre-set options

Available Call-to-Action Buttons

Reddit offers these CTA options:

• Learn More
• Shop Now
• Sign Up
• Download
• Apply Now
• Contact Us
• Get Quote
• Watch More
• See Menu
• Book Now
• Play Now

Headline Writing Tips

1. Include your primary keyword naturally
2. Lead with value proposition or hook
3. Avoid excessive caps or punctuation!!!
4. Match community tone—corporate speak underperforms
5. Test multiple headlines (3-5 variants recommended)

Best Practices for Each Format

Image Ads

Do:

• Use 4:5 portrait for mobile-first campaigns
• Add text overlay to images (but keep it minimal)
• Test meme-style creative against polished assets
• Include your logo subtly

Don't:

• Use heavy text overlays (reduces performance)
• Upload blurry or low-resolution images
• Use generic stock photos without customization
• Ignore aspect ratio recommendations

Video Ads

Do:

• Design for sound-off viewing (add captions)
• Hook viewers in the first 3 seconds
• Show actual product/service in action
• Keep optimal length around 60 seconds
• Use custom thumbnails

Don't:

• Start with logo animations (users scroll past)
• Rely on audio for key messaging
• Upload videos over 512 MB (slower processing)
• Use horizontal-only for mobile campaigns

Carousel Ads

Do:

• Tell a story across cards
• Use first card as the hook
• Maintain visual consistency
• Include CTA on final card

Don't:

• Mix aspect ratios across cards
• Use unrelated images
• Skip the narrative opportunity
• Overload with text per card

Conversation Ads

Do:

• Match the discussion topic authentically
• Prepare for user engagement (comments)
• Use educational/helpful content
• Keep headlines under 100 characters

Don't:

• Use aggressive sales language
• Ignore user comments
• Place in irrelevant threads
• Copy/paste feed ad content

Mobile vs. Desktop Considerations

Understanding device distribution is crucial for creative decisions:

Platform	Usage Share	Primary Format Recommendation
Mobile	70%+	4:5 portrait or 1:1 square
Desktop	~30%	16:9 or 4:3 landscape

Mobile-First Design Tips

• Assume sound-off viewing
• Use larger text overlays (readable at small sizes)
• Keep key content in center safe zone
• Test thumbnails at mobile preview size
• Front-load messaging (users scroll quickly)

Quick Reference Cheat Sheet

Copy this table for your creative team:

Image Ads Quick Specs

Dimensions: 1080×1080 (1:1), 1080×1350 (4:5), 1920×1080 (16:9)
File type: JPG, PNG
Max size: 3 MB
Headline: 150 chars (feed), 100 chars (conversation)

Video Ads Quick Specs

Dimensions: Same as image (1080×1080, 1080×1350, etc.)
File type: MP4, MOV
Max size: 1 GB (recommended under 512 MB)
Duration: 5-60 seconds recommended (max 15 min)
Frame rate: 30 FPS
Thumbnail: 400×300 px, JPG/PNG, max 500 KB

Carousel Ads Quick Specs

Cards: 2-6 per ad
Dimensions: Same as image ads
File type: JPG, PNG
Max size: 3 MB per card
All cards: Same aspect ratio required

Frequently Asked Questions

What's the best image size for Reddit ads?

For most campaigns, use 1080×1350 pixels (4:5 portrait) for mobile-first reach, or 1080×1080 pixels (1:1 square) for balanced mobile/desktop performance. These dimensions work well given that 70%+ of Reddit usage is mobile.

What video length works best on Reddit?

While Reddit allows videos up to 15 minutes, the optimal length is 60 seconds for engagement metrics. For awareness campaigns, 15-30 seconds works well. Always hook viewers in the first 3 seconds.

Can I use GIFs in Reddit ads?

Reddit accepts GIF files, but they get converted to static images. If you want animated content, use MP4 video format instead.

What's the maximum file size for Reddit ads?

Image ads: 3 MB maximum. Video ads: 1 GB maximum (512 MB recommended for faster processing). Carousel cards: 3 MB per card.

Why is my Reddit ad headline getting cut off?

Feed placements allow 150 characters, but conversation placements only allow 100 characters. If you're running multi-placement campaigns, keep headlines under 100 characters to ensure full visibility everywhere.

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Key Takeaways

• 4:5 portrait (1080×1350) is the optimal image/video ratio for mobile-dominant Reddit
• Keep video under 60 seconds with hook in first 3 seconds
• Headline limits differ by placement: 150 chars (feed) vs. 100 chars (conversation)
• File size limits: 3 MB images, 1 GB video (512 MB recommended)
• Always upload custom thumbnails for video ads
• Test multiple creative variants (3-5 per campaign recommended)

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Related reading: Complete Reddit Advertising Guide | Reddit Conversation Ads | Reddit Video Ads