Reddit ad specs and ad types

Every agency post about Reddit ad specs is the same table copied off the help centre. Here is the table, because you need it. Then here is the part nobody publishes: I pulled the top 40 posts of the last year from ten subreddits and measured what actually wins the feed, so you can see how far the spec sheet is from the brief.

What are the Reddit ad specs, in one table?

Four self-serve ad types, two placements. Feed covers Home, Popular and community feeds. Conversation puts you inside the comment thread.

The text limits are the same on all four formats, and one of them is a trap:

• Headline: 300 characters. Reddit's own image ad spec recommends 100 or fewer, and says keep it under 80 if truncation worries you.
• Destination URL: 268 characters. Display URL: 100, and it has to match the destination domain.
• Captions: 50 characters, one per card on a carousel, one per asset on a free-form.
• 23 calls to action to choose from.

Resolutions, if you only make one file: 1440 x 1080 at 4:3 covers desktop and mobile for images. For video, use 1200 x 1200 square or 1200 x 1500 at 4:5 for mobile and 1920 x 1080 for desktop. The conversation thumbnail is 400 x 300 and gets generated from your main asset unless you upload one. Free-form is the exception. It generates no thumbnail at all, so a free-form ad with no image uploaded shows up in the feed as pure text.

Why do Reddit's own numbers disagree with each other?

Because the marketing site and the help centre are maintained by different people.

Trust the help centre. It is the one the ad review process is built on, two of Reddit's three pages agree with it, and 1200 x 628 is a Facebook link-preview ratio that appears nowhere else in Reddit's documentation.

Which Reddit ad type is actually native?

Free-form, in most of the places you want to advertise. Here is what the feed actually looks like.

I pulled the top 40 posts of the past year from ten subreddits on 6 September 2026. 400 posts, median score 1,169, median 242 comments. By format:

• Plain text: 60%
• Single image: 23%
• Gallery: 14%
• Link: 2%, six posts
• Video: 1%, four posts

The split is not global, it is per subreddit, and it is close to binary.

So the answer to "image or video or carousel" is decided before you open the ads manager. Check the top of the subreddit you are buying. If it is a text community, an image ad with a stock photo and a Learn More button is a billboard nailed to a bulletin board, and every single person scrolling past has already learned to skip that shape. I wrote about the formats that survive contact with a feed before I had the numbers. The numbers are worse than I said.

What do the winning titles look like?

Short. Across the 400:

• Median 63 characters, mean 69
• 69% came in at 80 characters or under, 82% under 100
• 52% used first person somewhere, 21% opened with I, We, My, After or Just
• 19% ended in a question mark, 32% contained a digit
• Only 5% used an exclamation mark, and 6% had a run of four or more capital letters

That lines up with Reddit's truncation warning and it means the 300 character field is decorative. Write 63. The exclamation mark number rules out most of what a brand template will hand you.

Real shapes from r/smallbusiness this year: "I started leaving a simple one-pager after every job and my repeat calls went up" at 80 characters. "Got offered $1.5M cash for my business today. I'm 28. Talk me into it or out of it." at 83. Specific, first person, no product name, and the second one hands the thread a job to do.

Where does Reddit's own advice contradict the feed?

On brand names. Reddit ran a study of over 100,000 ads and found headlines including the brand name saw an average 6.5% conversion rate lift and CPA improvement, and that more than half of measured headlines skipped it. Adopting three of their top headline features lifts conversion rate by up to 12%.

I believe the study. It measures ads against other ads. None of the 400 organic winners led with a brand name, because organic posts are not selling anything, and the thing you are copying is the organic post. Those two facts pull in opposite directions and you have to pick a side per campaign. My rule: brand name in the free-form body where it reads as disclosure, not in the headline where it reads as a pitch. The authenticity argument is the same argument, one layer up.

Reddit gets the rest of it right and says it plainly. Their image ad guidance tells you to consider creator-style content that blends into the feed, and that a product demo shot on a phone can beat a studio shoot. Their best practices page says redditors dislike "sneaky" ads. 76% of Reddit browsing is mobile.

Is video worth buying at all?

Four posts out of 400. That is the entire organic case for video in these ten communities.

Video ads still work on Reddit, and they work as video ads, not as camouflage. Reddit's own guidance says show your brand in the first three seconds, add captions because sound is off, and that videos over 30 seconds tend to underperform. Every one of those instructions is telling you to look like an ad. Buy video when you want reach and you have accepted the ad tax. Buy free-form when you want the comment thread, because a free-form ad with comments enabled is the only unit that can end up looking like the 240 comment posts around it.

The spec sheet takes ten minutes to satisfy. Getting a 63 character first-person headline past your own brand team is the part that takes three weeks.