Reddit Ad Specs: Complete Guide to Formats and Sizes

16 Sep 2026 · 11 min read

Current Reddit ad specs vary by format and placement. Image ads support square, portrait, classic landscape, and widescreen creative, while video, carousel, free-form, and conversation placements each add their own requirements.

The catch: an asset can pass Reddit’s upload validation and still crop badly, truncate its message, or look weak in a conversation thread. Use the tables and checks below before you launch.

Reddit ad specs at a glance

Start with this master reference. Then confirm the final setup inside Reddit Ads Manager, since available fields can change by objective, placement, and account configuration.

Image, video, carousel, and text ad requirements

Image ads: Keep the message clear

Build image ads from a high-quality source file. Reddit accepts JPG, PNG, and GIF uploads, but GIFs become static images rather than animated ads. The official image-ad guide caps the image file at 3 MB.

Check each component separately:

• Creative asset: Use the aspect ratio that matches your intended placement.
• Headline: Lead with the product, problem, or outcome before supporting detail.
• Destination URL: Send users directly to the page promised by the ad.
• GIF handling: Choose a deliberate first-frame-style composition because the upload becomes a still image.
• Branding: Keep your logo readable without letting it dominate the visual.

Video ads: Design for muted viewing

Use an MP4 or MOV source file and frame the subject for mobile viewing. Keep captions and essential interface details away from crop-prone edges.

Make the opening visual understandable without sound. If the composer requests a thumbnail, choose one that communicates the same promise as the headline. Then test the complete path from video to landing page.

Carousel ads: Build a sequence

Do not treat a carousel as a stack of unrelated image ads. Give every card a role: establish the problem, show the workflow, explain a feature, or reinforce the next action.

Keep card crops, typography, and visual hierarchy consistent. Check every card-level headline and link individually. A strong opening card earns attention, while the remaining cards need to continue the same story.

Text-led ads: Support the post when needed

Text-led and free-form options can resemble native Reddit posts, but the required supporting assets depend on the format and objective. You may still need a visual, video, destination, or thumbnail.

Write like a useful post, not a compressed landing page. Be specific about the problem, state what the user will get, and make the destination match that promise.

The specs other guides confuse: limits, placements, and recommendations

This is where many Reddit ad spec guides go wrong. They blend validation rules with placement rules and performance advice, then present everything as a single universal limit.

Here is the headline correction most outdated guides miss: Reddit’s current image-ad specifications list a 300-character headline maximum and a 268-character destination URL maximum, while recommending headlines under 100 characters and placing the key message within the first 80 characters.

So a long headline may be valid but still display poorly. Passing validation only confirms acceptance. It does not guarantee clean presentation across feeds, devices, and previews.

Free-form ads also need their own treatment. Reddit’s free-form guidance recommends headlines under 80 characters, square images at 1200 × 1200 pixels, and video files between 50 and 100 MB. Those are format-specific creative recommendations, not universal image-ad limits.

How placement changes your Reddit creative

A Reddit placement changes the space around your ad, the context in which users see it, and how much of the creative appears before interaction.

Meet the feed: Scroll-first discovery

Feed creative competes with posts during active scrolling. Use an immediate visual subject, front-load the headline, and avoid tiny interface screenshots that require zooming.

Meet the conversation: Context-first attention

Conversation placements appear near active discussions. The thumbnail is more compact, so detailed charts, long overlay copy, and edge-positioned logos can become unreadable.

Meet other eligible placements: Preview before assuming

Eligibility does not mean identical rendering. Available space, text wrapping, and expansion behavior may differ based on device and interface.

Create a placement matrix before uploading:

This matrix gives every ad group a defined asset, message, and destination. It also stops teammates from attaching the right campaign idea to the wrong crop.

Safe zones, cropping, and mobile readability

Reddit does not give you one universal safe-zone measurement that works across every format and placement. Build a practical safe area instead: keep the logo, product name, captions, and call to action away from the outer edges.

• Square: Flexible in compact cards, but wide product screenshots may become too small.
• Portrait: Gives the creative more vertical presence, but edge content may suffer when shown in a shorter preview.
• Landscape: Works well for broad scenes and interface demonstrations, though small text can disappear on mobile.
• Classic landscape: Offers a middle ground, but still needs a deliberate focal point near the center.

Preview the design as a Reddit user will experience it, not as a designer viewing the full canvas.

• Reduce the preview to a small-screen size.
• Check light and dark interfaces.
• Inspect feed and conversation crops.
• Look for headline truncation and awkward line breaks.
• Play video muted and confirm the opening still makes sense.
• Compare the ad promise with the landing-page headline and visual.

How to prepare and upload compliant creative

1. Choose the ad type and placement. Decide whether you need image, video, carousel, or free-form creative before opening your design tool.
2. Select the matching template. Use a source canvas built for the intended ratio rather than stretching an existing export.
3. Export the asset. Confirm dimensions, file type, file size, animation behavior, and video compatibility.
4. Validate copy and destination fields. Front-load the headline, check spelling, and verify that the URL leads to the promised page.
5. Upload in Ads Manager. Read platform warnings instead of dismissing them as generic notices.
6. Inspect every preview. Check cropping, text wrapping, thumbnail behavior, muted playback, and mobile readability.
7. Resolve warnings and approve. Replace the source asset when necessary rather than repeatedly compressing a weak export.

Preflight checklist

• Dimensions match the intended aspect ratio.
• File format is accepted for the chosen ad type.
• File size meets the applicable upload requirement.
• GIF behavior is understood before launch.
• Video encoding and playback work after upload.
• The correct thumbnail is attached.
• Headline, overlay copy, and captions are proofread.
• Destination and URL parameters are tested.
• Creative and copy comply with Reddit’s current advertising policies.
• A human reviewer has inspected the final placement previews.

Use descriptive file names that identify the format, placement, crop, message, and revision. For example, write the name in that order and use consistent labels across design files, exports, and campaign records.

Avoid names such as final-new-approved. They hide the information your team needs when replacing an asset under pressure.

Reddit ad specs FAQ and launch checklist

What is the best image shape for Reddit ads?

There is no universal winner. Choose square or portrait when mobile visibility matters, and landscape when the subject genuinely needs horizontal space. Let the placement preview decide.

Do GIF ads animate on Reddit?

No. Reddit accepts GIF uploads for image ads but converts them to still images. Design the chosen frame as if it were a standard static ad.

Why did Reddit accept an image that crops poorly?

Upload validation checks technical acceptance. It does not promise that every placement will preserve your full composition. Cropping and compact previews can still hide edge content or shrink overlay text.

Can I use the same creative across every placement?

You may be able to use the same source concept, but you should not assume one export will display well everywhere. Prepare alternate crops, a conversation thumbnail, and shorter copy where the preview requires them.

Where should I confirm future specification changes?

Check the live Ads Manager composer and the relevant Reddit for Business specification guide before each launch. Treat saved templates and third-party articles as working references, not permanent platform rules.

Copy-and-paste launch checklist

• Creative matches the selected format and placement.
• All placement previews have been inspected.
• Mobile text and product details remain readable.
• Conversation thumbnails use the correct crop.
• Muted video still communicates the core message.
• Destination pages load and match the ad promise.
• Tracking parameters are present and tested.
• Required disclosures are visible and accurate.
• Current Reddit policies have been reviewed.
• Final creative, copy, targeting, and destination have human approval.

Short takeaway: Build to the format, adapt to the placement, and preview before approving. Your next step is to create a placement matrix for the campaign you are preparing now.