Getting the right Reddit ad specs sounds simple until you start building creative and discover that image ads, video ads, carousel ads and conversation placements all have different requirements.
It gets more confusing because older Reddit ad size guides still recommend a single 1200 × 628 image for almost everything. Reddit’s current guidance is more flexible. Image ads now support square, portrait and landscape creative, while video and carousel formats have their own file, duration and placement requirements.
This guide brings the main Reddit ad sizes, dimensions, file limits and character limits for 2026 into one place.
Reddit ad specs at a glance
| Reddit ad format | Recommended size / format | File limit | Main text limit |
|---|---|---|---|
| Image Ad | 1080 × 1080, 1080 × 1350, 1440 × 1080, 1920 × 1080 | 3 MB in Reddit’s 2026 image spec guide | 300-character headline |
| Video Ad | 1:1, 4:5 or 16:9 | 1 GB | 300-character headline |
| Carousel Ad | 2 to 6 images or GIFs | Depends on asset type | 300-character headline |
| Conversation Placement | Uses the underlying image, video or carousel format | Depends on format | Shorter headlines recommended |
| Conversation Thumbnail | 400 × 300 px | Under 500 KB | N/A |
| Free-form Ad | Rich text with optional image, GIF or video | Depends on media | Keep headline under 80 characters to avoid cutoffs |
One important detail: Reddit’s dedicated 2026 image-spec guide lists a 3 MB maximum image size, while some Reddit ad-type overview pages still reference a larger 20 MB limit for JPEG and PNG assets. For production, we recommend treating 3 MB as the safe image limit unless Ads Manager explicitly accepts a larger file. See Reddit’s current image ad specifications.
Reddit image ad specs
Image ads are the simplest Reddit ad format and usually the best starting point if you are testing the platform for the first time.
Reddit currently recommends four main image sizes:
| Aspect ratio | Recommended Reddit image size | Best suited for |
|---|---|---|
| 1:1 | 1080 × 1080 px | Flexible mobile and desktop creative |
| 4:5 | 1080 × 1350 px | Mobile-first feed ads |
| 4:3 | 1440 × 1080 px | Landscape product or UI creative |
| 16:9 | 1920 × 1080 px | Wide screenshots and desktop creative |
Supported formats are JPG, PNG and GIF, although a GIF uploaded as a standard image ad is displayed as a static image. Reddit’s dedicated 2026 image guide lists a maximum image file size of 3 MB and allows headlines of up to 300 characters. Reddit also recommends previewing every crop because images may render differently across placements and devices.
What is the best Reddit image ad size?
For most campaigns, we would build 1080 × 1350 px (4:5) first. The extra vertical space gives you more screen real estate in a mobile feed without going into full-screen vertical-video territory. For a second variation, create a 1080 × 1080 px square version.
If the creative depends on a product dashboard, screenshot or wider comparison graphic, 1440 × 1080 or 1920 × 1080 may be easier to read.
What is the Reddit banner size?
Reddit banner size is a common search, but Reddit does not treat standard self-serve promoted posts as traditional display banners. In most cases, someone looking for the Reddit banner ad size actually needs the image ad specifications above.
For a standard feed campaign, use 1080 × 1350 px for mobile-first portrait creative, 1080 × 1080 px for square creative, 1440 × 1080 px for 4:3 landscape, or 1920 × 1080 px for 16:9.
Reddit image ads can appear in mobile and desktop feeds, with some configurations also supporting desktop right-rail placement. Always check the placement preview instead of assuming one crop will render identically everywhere.
Reddit video ad specs
Reddit video ads autoplay in feeds and can run across desktop and mobile. Reddit’s current ad-type documentation lists MP4 and MOV as supported formats, a maximum file size of 1 GB, and supported aspect ratios of 1:1, 4:5 and 16:9.
Videos can run for up to 15 minutes, although Reddit recommends keeping them to 60 seconds or less for most campaigns.
| Aspect ratio | Practical export size | Use case |
|---|---|---|
| 1:1 | 1200 × 1200 px | Flexible square creative |
| 4:5 | 1200 × 1500 px | Mobile-first feed video |
| 16:9 | 1920 × 1080 px | Wide product demos and explainers |
For most performance campaigns, 4:5 at 1200 × 1500 px is a practical mobile-first choice.
Do not design a Reddit video assuming users will hear the audio. Make sure the opening works visually, and use captions or on-screen text when the message depends on dialogue.
Reddit carousel ad specs
Carousel ads are useful when one image is not enough to communicate the offer. They work particularly well for product features, comparisons, step-by-step stories and multiple products.
Reddit currently supports 2 to 6 images or GIFs in a carousel. The format can appear in feed and conversation placements, and individual cards can support their own captions and links. Reddit’s current ad-type comparison confirms the 2 to 6 asset structure.
Keep every carousel card in the same aspect ratio. Even when mixed sizes upload, transitions can look inconsistent and important information may be cropped differently across cards.
For a SaaS carousel, a useful sequence is Problem → Feature → How it works → Proof → CTA. That lets the user understand the story by swiping instead of forcing several disconnected product screenshots into one ad.
Reddit conversation ad specs
One distinction worth making is that a Conversation Ad is primarily a placement, not an entirely separate creative format.
Conversation placements put an ad inside Reddit’s discussion experience, where users are already reading replies and comments. The underlying creative can use supported Reddit formats, so its primary requirements still depend on whether you are running an image, video or carousel ad.
For conversation placement, Reddit’s 2026 image guidance specifies an optional custom thumbnail of 400 × 300 px, using JPEG or PNG, and under 500 KB.
This matters because a beautifully designed feed image can become difficult to recognise when reduced to a small conversation thumbnail. Keep logos, product names and the core visual idea large enough to survive the smaller placement.
Reddit free-form ad specs
Free-form Ads are one of Reddit’s more distinctive formats. Instead of forcing an advertiser into a conventional image-plus-headline structure, they can combine long-form text, images, GIFs, video and links into something closer to an organic Reddit post.
Reddit’s current Free-Form Ads guidance recommends keeping headlines under 80 characters to avoid cutoffs. For images, Reddit highlights square 1200 × 1200 px creative and wide formats such as 1440 × 1080 px or 1920 × 1080 px. For video used inside a free-form ad, Reddit suggests aiming for a file size around 50 to 100 MB.
Free-form ads can be particularly useful when the audience needs more context before they click. That makes them interesting for technical SaaS products, developer tools and categories where buyers want an explanation rather than another polished product graphic.
Reddit ad headline character limits
Reddit allows headlines of up to 300 characters for standard image and video ads. That does not mean you should use all 300.
Reddit’s image-spec guidance recommends keeping headlines closer to 100 characters or fewer, particularly because copy can truncate across devices and placements. For free-form ads, Reddit recommends staying under 80 characters.
For B2B SaaS campaigns, the first part of the headline should explain either the problem, outcome or reason to care. A vague line such as “AI-powered platform to transform your workflow” wastes the most valuable part of the ad. A specific line such as “Still manually checking 200 customer calls?” gives the reader a reason to stop.
Which Reddit ad size should you actually create?
You do not need designers exporting every possible Reddit size before the first test. For most campaigns, our practical starting set would be:
| Requirement | Creative we would build first |
|---|---|
| Primary static ad | 1080 × 1350 image |
| Secondary static variation | 1080 × 1080 image |
| Video | 1200 × 1500 |
| Wide product/demo creative | 1920 × 1080 |
| Carousel | Consistent square or portrait cards |
| Conversation thumbnail | 400 × 300 |
That gives you enough flexibility to test Reddit’s main placements without creating dozens of nearly identical files.
Common Reddit ad size mistakes
- Relying on an old 1200 × 628-only template.
- Putting important copy too close to the edge.
- Expecting an Image Ad GIF to animate.
- Using the entire 300-character headline allowance.
- Mixing aspect ratios inside a carousel.
- Approving an ad without checking both feed and conversation previews.
The technical specification is only the first check. A file can satisfy the upload requirements and still perform badly because the copy is unreadable on mobile or the important part of the image gets lost in another placement.
Reddit ad specs for B2B SaaS campaigns
For B2B SaaS, ad size is only part of the equation. Reddit behaves differently from LinkedIn or Meta because users organise themselves around communities, problems and interests instead of primarily around job titles.
That makes Reddit particularly interesting for technical products, developer tools and niche SaaS categories where potential customers actively discuss the problem you solve.
If you are deciding how the channel fits your acquisition strategy, read our Reddit Ads for SaaS guide. If you want help planning and managing campaigns, see our Reddit Ads agency service.
You can also review OneMetrik’s broader paid media agency approach or request a free ads audit if you want an outside view of your current paid media setup.
Frequently Asked Questions
What is the best size for a Reddit ad?
For most Reddit image ads, start with 1080 × 1350 px in a 4:5 aspect ratio for mobile-first creative. A 1080 × 1080 px square version is also useful for broader placement coverage. Reddit supports multiple aspect ratios, so the best size depends on the ad format and placement.
What are the Reddit video ad specs?
Reddit video ads support MP4 and MOV files up to 1 GB. Current Reddit guidance supports 1:1, 4:5 and 16:9 aspect ratios, with videos running up to 15 minutes. For most feed campaigns, shorter mobile-first creative is a better starting point.
How many images can you use in a Reddit carousel ad?
A Reddit Carousel Ad can contain 2 to 6 images or GIFs. Keep the cards in a consistent aspect ratio so the carousel looks clean across feed and conversation placements.
What is the character limit for a Reddit ad headline?
Standard Reddit image and video ads allow headlines of up to 300 characters. However, shorter headlines are usually better because text can truncate across devices and placements. Reddit’s current image guidance recommends keeping the key message within roughly the first 100 characters.
What ad formats are available on Reddit?
Reddit’s main self-serve formats include image ads, video ads, carousel ads and free-form ads. Advertisers can also use conversation placement, which displays supported creative inside Reddit discussion threads.
Final checklist before uploading Reddit ad creative
- Use one of Reddit’s supported aspect ratios for the selected ad format.
- Keep static images compressed and safely within the current file-size guidance.
- Check the mobile and desktop previews before launch.
- Keep the most important text away from crop-prone edges.
- Use short, specific headlines even though Reddit allows up to 300 characters on standard ads.
- Prepare a dedicated 400 × 300 thumbnail when conversation placement needs tighter creative control.
- Keep carousel cards visually consistent.
- Recheck Reddit’s official ad specifications whenever you refresh creative, because formats and limits can change.