What is the recommended image size for a Reddit ad?

Reddit recommends a 1200 by 628 pixel image for feed and conversation ads, with 1:1 and 4:5 also supported. Larger square or portrait creative often performs better on mobile because it takes more vertical space in the feed.

What is the headline character limit for a Reddit ad?

Reddit ad headlines are limited to 300 characters, the same as an organic post title, but the feed truncates the preview well before that. Keep the core message inside roughly the first 100 characters for full visibility.

How many cards can a Reddit carousel ad have?

A Reddit carousel ad supports between 2 and 6 cards. Each card has its own image, headline, and destination URL, so order them with the strongest hook first because most users only swipe a card or two.

What file formats and sizes does Reddit accept for ads?

Image ads accept PNG and JPG up to about 500 KB, while video ads accept MP4 and MOV up to 1 GB. Reddit re-encodes uploads, so provide the highest-quality source within the caps to avoid visible compression.

How long can a Reddit video ad be?

Reddit video ads run from 5 seconds to 30 minutes, but the most effective creatives stay under 30 seconds. Add captions because most feed video first plays muted, and front-load your brand and offer.

Reddit Ad Spec Reference

Email me this result

Get this tool's output sent to your inbox, plus one useful tool a week. No spam, unsubscribe any time.

Reddit’s ad formats each have their own pixel dimensions, file-size caps, and copy limits, and getting any of them wrong can stall ad review. This reference returns the full spec for every Reddit ad placement so your creative and copy pass the first time.

How it works

Select an ad format and the tool returns its complete specification:

Image size — the recommended pixel dimensions and accepted aspect ratios.
File limits — accepted formats and the maximum upload size.
Copy limits — the headline and body character caps Reddit enforces.
Format rules — card count for carousels and duration for video.

These figures reflect Reddit’s published ad specifications. Where Reddit accepts a range of ratios, the recommended one for mobile is listed first.

Tips and notes

Square (1:1) and portrait (4:5) creative usually outperforms landscape on Reddit because mobile dominates and vertical formats claim more feed space. Keep headlines tight — the preview truncates long before the 300-character cap — and always caption video, since feed playback starts muted. All lookups run locally in your browser.