Reddit Ad Specs, Sizes & Types (2026)
Updated: 7 days ago
Reddit ads come in four main formats: image, video, carousel, and free-form. Images and videos work in five ratios: 4:5 (1200 × 1500), 4:3 (1440 × 1080), 1:1 (1200 × 1200), 16:9 (1920 × 1080) and 3:4 (900 × 1200). Headlines can be up to 300 characters, but Reddit recommends keeping them under 100. Below are the full specs for each format, plus the mistakes that get ads cut off or letterboxed.
What are the Reddit ad specs in 2026?
Here are the core specs for every self-serve Reddit ad format:
Format | Sizes | Files | Text limits |
|---|---|---|---|
Image | 1200×1500 (4:5), 1440×1080 (4:3), 1200×1200 (1:1), 1920×1080 (16:9), 900×1200 (3:4) | JPG, PNG, up to 3 MB | Headline up to 300 characters |
Video | Same five ratios as image | MP4, MOV (no ProRes), up to 1 GB | Headline up to 300 characters, video 2 seconds to 15 minutes |
Carousel | 2 to 6 cards, same ratio on every card | Images or GIFs | One headline, captions up to 50 characters per card |
Free-form | Media inside the post, plus a thumbnail you upload | Images and videos | Headline up to 300 characters, body up to 40,000 characters |
Image ads can be up to 3 MB. Other formats have their own file size limits, so check the limit in Ads Manager when you upload.
What image size is best for Reddit ads?
Use one of the five supported ratios at the highest resolution you have, and keep the file under 3 MB. Reddit accepts any ratio, but an off-size image gets letterboxed, which means black or blank bars around your picture. Reddit's own best practices put 4:5 and 4:3 first.
4:5 (1200 × 1500): tall, so it fills most of a phone screen. Our first pick for the feed.
4:3 (1440 × 1080): a safe choice that looks right on both desktop and mobile.
1:1 (1200 × 1200): a clean square that works everywhere.
16:9 (1920 × 1080): wide, best for video and for images cut from video.
3:4 (900 × 1200): the tallest option, for creative shot vertically.
Image and video ads can also use an optional thumbnail. Reddit shows it in compact view and in conversation placements. If you don't upload one, Reddit makes it from your image.
What are the Reddit video ad specs?
File type: MP4 or MOV, up to 1 GB. ProRes isn't supported.
Ratios: the same five as image ads. Start with 4:5 or 4:3.
Length: 2 seconds to 15 minutes. Reddit recommends 5 to 30 seconds.
Export: H.264 at up to 30 frames per second is the safest setting for review and playback.
Playback: video ads autoplay in feeds on desktop and mobile, so your first seconds do most of the work.
More detail, including which ratio to pick for each placement, is in our Reddit video ad specs guide.
What are the Reddit carousel ad specs?
A carousel ad has one headline, 2 to 6 swipeable cards, and a link. Each card can have its own caption (up to 50 characters) and its own destination. Use the same ratio on every card, or some cards will look cropped.
Carousels work well for showing several products, or telling a short story one card at a time.
What are Reddit free-form ads?
Free-form ads look like a normal Reddit post. You can mix text, images, and videos in one ad, with a headline up to 300 characters and a body up to 40,000 characters.
The one rule people miss: free-form ads don't make a thumbnail for you. If you skip it, your ad shows in the feed with no picture at all. Always upload one.
Keep the first few lines of the body clear and useful, because that's all people see in the feed before they click.
What types of Reddit ads are there?
Image ads: one image, a headline, and a link. The simplest way to start.
Video ads: autoplay in the feed. Good for showing a product in action.
Carousel ads: 2 to 6 swipeable cards. Good for several products or steps.
Free-form ads: long, post-style ads that fit in best with how Reddit looks.
AMA ads and Reminder ads: newer formats for live events and launches (AMA ads are in beta).
Max campaigns: not a format but a campaign type. You give Reddit your headlines and media, and it picks the best mix. See our Reddit Max case study.
Takeovers: premium placements sold through Reddit's sales team on a cost-per-thousand-views basis. Most follow the image and video specs.
For a full breakdown of every format, see Reddit ad types explained.
Ads can show in two places: the feed, and inside comment threads (conversation placements). Reddit recommends using both for the best reach.
How long should a Reddit ad headline be?
The limit is 300 characters, but Reddit recommends under 100, or under 80 if you're worried about it getting cut off. How much shows depends on the device and browser. Our study of 43,000+ Reddit ads looks at which headline lengths advertisers actually use.
Should you turn comments on for Reddit ads?
You can turn comments on or off for each ad. We recommend keeping them on. Comments show that real people are talking about your product, and a fast, honest reply from your brand builds more trust than the ad itself. The catch is that someone has to answer them, which is why ad comment reply management is part of our service.
Reddit ad specs: FAQ
What size should a Reddit ad image be?
Use 1200 × 1500 (4:5), 1440 × 1080 (4:3), 1200 × 1200 (1:1), 1920 × 1080 (16:9) or 900 × 1200 (3:4), as a JPG or PNG up to 3 MB. Other sizes get letterboxed.
How long can a Reddit video ad be?
Between 2 seconds and 15 minutes. Reddit recommends 5 to 30 seconds, because feed videos autoplay and people decide fast.
How many characters can a Reddit ad headline have?
Up to 300. Reddit recommends under 100 characters, or under 80 to avoid being cut off.
Do Reddit free-form ads need a thumbnail?
Yes. Free-form ads are the only format where Reddit doesn't create one for you. Without it, the ad shows no picture in the feed.
How many cards can a Reddit carousel ad have?
Between 2 and 6. Use the same ratio on every card.
Get your Reddit ads right the first time
Specs get your ad approved. Targeting and creative get it results. Find the right communities with our free subreddit finder, or get a Reddit Ads Game Plan built around your goals. See what's possible in our Reddit ads case studies.
Sources: Reddit Ads Help Center, Ad Unit Specifications, Free-form Ad Specifications, and Carousel Ad Specifications. Specs checked October 2026.
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About the author
Written by Dāvis Lejnieks, CEO of Undecided Agency and a Redditor for 15+ years. He plans and runs Reddit ad campaigns for DTC, gaming and app brands, and shares what the data shows here.
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