Reddit Ad Specs & Creative Checker
Every Reddit ad format's file types, sizes, aspect ratios and lengths in one table, plus a checker that tells you if your image or video meets them before you upload it to Ads Manager.
Your file is checked in your browser and never uploaded. Specs are taken from Reddit for Business's ad format pages.
| Format | Creative specs | Placement | Billing |
|---|---|---|---|
| Image ad | JPEG or PNG, up to 20 MB, 1:1 or 16:9, at least 1200 × 628 px | In-feed on mobile and desktop; optional right rail on desktop | CPM or CPC |
| Video ad | MP4 or MOV, up to 1 GB, 1:1, 4:5 or 16:9, up to 15 minutes (60 seconds or less recommended) | In-feed on mobile and desktop; conversation feed on desktop | CPM or CPV (minimum CPV bid $0.01) |
| Carousel ad | 2 to 6 images, JPG, PNG or GIF | Feed and conversation placements | Depends on objective |
| Conversation ad | Same specs as the underlying ad type | Conversation pages, inside comment threads | CPM or CPC, depending on campaign setup |
| Free-form ad | Rich-text post with optional images or video | Feed and conversation | Same model as the objective |
Check your creative
Pick an image or video file to check it against Reddit's specs.
Video best practices from Reddit
- Build for mobile with a 4:5 aspect ratio.
- Keep video ads under 10 seconds where you can.
- Show your logo in the first or the last 3 seconds.
About this tool
A free tool by GrowReddit, part of our free Reddit marketing tools. No account or signup required.
Quick Answer
What is the Reddit Ad Specs & Creative Checker?
Reddit ad specs for image, video, carousel, conversation and free-form ads, plus a checker that validates your image or video file in the browser. Available free at GrowReddit.com: no account, no signup required.
Specs as published on Reddit for Business's ad format pages, checked October 2026.
Tool Facts
- Price
- Free
- Signup
- Not required
- Powered by
- Runs in your browser (no AI model)
- Provider
- GrowReddit
- Category
- Reddit Marketing
In-depth guide: Reddit Ad Specs & Creative Checker
Practical guidance that matches how Reddit communities actually work, written specifically for this tool.
Reddit ad formats at a glance
Reddit offers five main ad formats. Image ads are the quickest to launch and cheapest to produce. Video ads autoplay in the feed and are best for recall and storytelling. Carousel ads show 2 to 6 images in one unit. Conversation ads appear inside comment threads, where people are actively reading. Free-form ads look like a rich-text Reddit post and suit longer, native-feeling messages.
All of them are bought in the same auction and appear labelled as promoted. The table above lists each format's creative specs as Reddit publishes them.
Creative tips that work on Reddit
- Make the headline sound like a post in the subreddit you're targeting, not a slogan.
- Use square (1:1) images and 4:5 video so the ad fills more of the mobile screen.
- Avoid stock photos; screenshots, product UI and simple charts tend to blend in better.
- Keep text on images short; the headline does the talking.
- Turn comments on and plan to reply. Ads that answer questions in the comments build trust.
After the creative: tracking
Before spending, make sure the Reddit Pixel is installed and firing the events you'll optimise for, such as Lead or SignUp. The Reddit Pixel Checker shows whether your site loads the pixel and which events it sends.
If you want to go one step deeper, pair this with Reddit Trend Spotter and Reddit Hook Generator. If you'd rather have the strategy executed end-to-end, see Reddit post promotion service or Reddit comment marketing service.
How to use Reddit Ad Specs & Creative Checker (step-by-step)
Use this as a starting point. The best results come from tailoring the final version to subreddit rules and the thread's tone.
- 1
Find your ad format
Look up the file type, maximum size, aspect ratio and length for the format you're running.
- 2
Check your file
Choose your image or video. The checker reads its dimensions, size and length in your browser.
- 3
Fix and upload
Resize or trim anything flagged, then upload to Reddit Ads Manager.
When this works best
These are real scenarios where the tool helps you move faster, without sacrificing authenticity.
Briefing a designer
Send one table with every Reddit format's specs instead of digging through help pages.
Pre-flight checks
Catch a wrong aspect ratio or an oversized file before Ads Manager rejects it or crops it badly.
Choosing a format
Compare placements and billing models side by side to pick the right format for your objective.
Reddit Ad Specs & Creative Checker: Frequently Asked Questions
Common questions about the free Reddit Ad Specs & Creative Checker tool on GrowReddit.
GrowReddit plans, designs and runs Reddit Ads for B2B SaaS
Native-feeling creative, the right subreddits, and reporting on qualified leads.
No signup required. Value-first approach. We never recommend spam tactics.
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