Image Specs
Post Image
| Dimensions | Up to 4000 × 4000 px |
|---|---|
| Aspect Ratio | Any (1.91:1 recommended for feed display) |
| Max File Size | 20 MB |
| File Formats | JPG, PNG, GIF |
| Notes | Gallery posts support up to 20 images |
Gallery Post
| Dimensions | Up to 4000 × 4000 px per image |
|---|---|
| Max File Size | 20 MB per image |
| File Formats | JPG, PNG, GIF |
| Notes | Up to 20 images; each can have its own caption (180 characters) — caption limit could not be independently corroborated against a second current source and is flagged as unverified |
[Ad]
Video Specs
Post Video
| Aspect Ratio | Any; 16:9 displays best |
|---|---|
| Max File Size | 1 GB |
| File Formats | MP4, MOV |
| Resolution | 1920 × 1080 px recommended |
| Max Duration | Up to 15 minutes |
| Notes | H.264 codec; audio optional but supported; GIF-style looping also available |
Text & Character Limits
Post Title
| Character Limit | 300 characters |
|---|---|
| Notes | Required; shown in feed and search results |
Post Body (Text)
| Character Limit | 40,000 characters |
|---|---|
| Notes | Rich text editor; supports Markdown formatting |
Comment
| Character Limit | 10,000 characters |
|---|
Profile Bio
| Character Limit | 200 characters |
|---|
Username
| Character Limit | 20 characters |
|---|---|
| Notes | Cannot be changed after creation |
Subreddit Name
| Character Limit | 21 characters |
|---|
Profile & Cover Assets
Avatar
| Dimensions | 256 × 256 px minimum |
|---|---|
| Max File Size | 10 MB |
| File Formats | JPG, PNG |
| Notes | Displayed as a circle |
Profile Banner
| Dimensions | 1920 × 384 px recommended (5:1) |
|---|---|
| Max File Size | 10 MB |
| File Formats | JPG, PNG |
| Notes | Secondary sources disagree on exact recommended size (1920×384 vs. 1200×400 both cited); center-third is the safe zone since edges crop on narrow screens. Not independently confirmable via official Reddit help pages, which returned 403 to automated fetch — flagged as uncertain |
Subreddit Icon
| Dimensions | 256 × 256 px |
|---|---|
| Max File Size | 500 KB |
| File Formats | JPG, PNG |
| Notes | Displayed as a circle; some Reddit Help pages reference 300×300 px instead of 256×256 px — flagged as a minor source disagreement |
Subreddit Banner
| Dimensions | Up to 4000 px wide × 192 px tall (large); 1920 × 256 px (medium) or 1920 × 128 px (small) also supported |
|---|---|
| Max File Size | 10 MB |
| File Formats | JPG, PNG |
| Notes | Corrected from a previous 4000×640 figure that isn't supported by current Reddit Mods documentation; banner height options are 128/256/384px tiers per Reddit's official mod help content |
Ad Specs
Promoted Post (Image)
| Dimensions | 1080 × 1350 px (4:5, recommended for mobile) or 1080 × 1080 px or 1920 × 1080 px (16:9) |
|---|---|
| Max File Size | 20 MB (static images); 3 MB (GIFs) |
| File Formats | JPG, PNG, GIF |
| Notes | 4:5 portrait performs best since 70%+ of Reddit usage is mobile; secondary sources disagree on file-size cap (some cite a flat 3 MB, others 20 MB static / 3 MB GIF) — flagged as uncertain, unable to confirm on ads.reddit.com directly |
Promoted Post (Video)
| Max File Size | 1 GB |
|---|---|
| File Formats | MP4, MOV |
| Resolution | 1920 × 1080 px or 1080 × 1080 px |
| Max Duration | 2 seconds to 15 minutes |
Carousel Ad
| Dimensions | 1080 × 1080 px per card |
|---|---|
| Max File Size | 20 MB per card (static); 3 MB per card (GIF) |
| File Formats | JPG, PNG, GIF |
| Notes | 2–6 cards per carousel |
Ad Headline
| Character Limit | 300 characters |
|---|
Ad Body
| Character Limit | 500 characters |
|---|