A 3840 × 2160 PNG
A 3840 × 2160 PNG of about 6 MB matches YouTube’s recommended size and fits the 50 MB computer limit, but is over the 2 MB limit for setting a thumbnail from the YouTube app.
YouTube thumbnail size checker
The YouTube thumbnail size is 3840 × 2160 pixels (16:9) for a video and 2160 × 3840 (9:16) for a Short, at least 640 pixels wide for a video. Save it as a JPG or PNG under 50 MB from a computer or 2 MB from the YouTube app. Custom thumbnails need a verified channel. Choose an image below to check yours.
Check your YouTube thumbnail
Choose Video or Short, then pick an image. The checker reads its size in your browser and tests it against every rule below; nothing is uploaded.
What size is a YouTube thumbnail?
3840 × 2160 pixels, a 16:9 ratio, for a regular video. YouTube’s help centre asks for a thumbnail “as large as possible”, because it is also the preview image in the embedded player, and sets the minimum width at 640 pixels. The 1280 × 720 size many guides still give uploads too, but it looks soft on a large or 4K screen. Every thumbnail YouTube describes, read on 4 November 2026:
| Thumbnail | Recommended size (px) | Ratio | Minimum | Largest file |
|---|---|---|---|---|
| Video | 3840 × 2160 | 16:9 | 640 px wide | 50 MB (computer), 2 MB (app) |
| Short | 2160 × 3840 | 9:16 | 640 px tall | 50 MB, computer only |
| Podcast playlist | A square image | 1:1 | Not stated by YouTube | 50 MB (computer), 10 MB (app) |
What file size and format does YouTube accept for thumbnails?
A JPG or PNG file, under 50 MB when you upload it in YouTube Studio on a computer. The YouTube app is stricter: 2 MB for a video thumbnail and 10 MB for a podcast. A 3840 × 2160 PNG can run to several megabytes, so set big thumbnails from a computer, or save them as a high-quality JPG, which is usually a fraction of the size. The free image compressor and image converter do both in the browser.
What size is a YouTube Shorts thumbnail?
2160 × 3840 pixels, a 9:16 ratio, with a minimum height of 640 pixels. YouTube only lets you add a custom Shorts thumbnail in YouTube Studio on a computer, under Content, then Shorts. One quirk: on the home, Explore and subscription pages, a vertical video with a 16:9 thumbnail is shown with an auto-generated 4:5 thumbnail instead, so give vertical videos a 9:16 thumbnail. For the rest of a channel’s images, banner and profile picture, see YouTube image sizes.
How do you make a YouTube thumbnail the right size?
- Design at 3840 × 2160 pixels. Start on YouTube’s recommended 3840 × 2160 canvas for a video, or 2160 × 3840 for a Short, so the thumbnail stays sharp on every screen, from a phone to a 4K TV.
- Keep the 16:9 shape. Use 16:9 for a regular video, matching the player, and 9:16 for a Short, so the thumbnail fills its slot without bars or cropping.
- Stay above 640 pixels. Never export a video thumbnail narrower than 640 pixels, or a Shorts thumbnail shorter than 640 pixels: that is YouTube’s minimum.
- Save a JPG or PNG under the limit. Keep the file under 50 MB for YouTube Studio on a computer, or under 2 MB if you set it from the YouTube app.
- Check it, then upload. Run the image through the checker on this page, then upload it in YouTube Studio or add it as the cover when you schedule the video.
What does it look like in practice?
A 1280 × 720 JPG
A 1280 × 720 JPG of about 300 KB is above the 640-pixel minimum and under the 2 MB phone limit, so it uploads from anywhere, though it is less sharp on a 4K screen.
A 400-pixel-wide image
An image 400 pixels wide is below YouTube’s 640-pixel minimum width, so YouTube does not accept it as a video thumbnail.
How do you add a custom thumbnail on YouTube?
In YouTube Studio on a computer, per YouTube’s help centre:
Open Content
Sign in to YouTube Studio and choose Content in the left menu; for a Short, choose Shorts at the top.
Open the video
Select the video or Short and open its details.
Upload the thumbnail
Under Thumbnail, choose Upload file and pick your image, or Get suggestions to let YouTube generate options.
Save
Select Save. The new thumbnail can take a little while to appear across YouTube.
Why can’t you upload a custom thumbnail on YouTube?
Usually because the channel is not verified. Custom thumbnails are one of the features YouTube unlocks once you verify the account with a phone number at youtube.com/verify; until then, you can only choose a frame YouTube generates from the video. Two other limits apply: a channel can upload only so many custom thumbnails a day (the error reads “Daily custom thumbnail limit reached”, so try again in 24 hours), and repeated Community Guidelines strikes can remove custom thumbnails for 30 days.
How do you test YouTube thumbnails?
With YouTube Studio’s A/B test, on a computer. Under Thumbnail, choose A/B Testing and upload up to 3 thumbnails, titles or both. YouTube splits viewers between them and, usually within two weeks, shows everyone the version with the most watch time. Shorts, scheduled live streams and premieres cannot be tested, and changing the title or thumbnail during a test stops it.
How do you set a YouTube thumbnail when you schedule a video?
In SkedCast, attach the video, then set its cover: upload a thumbnail image, or pick a frame from the video, which SkedCast captures as a JPG. Without either, SkedCast uses a representative frame from the start of the video. When the video publishes, SkedCast uploads it and sets the cover as its thumbnail straight away; in a bulk import, each row can carry its own thumbnail URL. The channel must be verified for custom thumbnails, and if YouTube refuses a cover, the post says why. See every YouTube option on the YouTube scheduling page.
YouTube thumbnail size FAQ
- What size is a YouTube thumbnail?
- YouTube recommends 3840 × 2160 pixels, a 16:9 ratio, for a video thumbnail, with a minimum width of 640 pixels.
- What size is a YouTube thumbnail in pixels?
- 3840 × 2160 pixels for a video and 2160 × 3840 for a Short. The older 1280 × 720 still uploads, since it is above the 640-pixel minimum.
- What is the YouTube Shorts thumbnail size?
- 2160 × 3840 pixels, a 9:16 ratio, with a minimum height of 640 pixels. Shorts thumbnails can only be added in YouTube Studio on a computer.
- What is the maximum file size for a YouTube thumbnail?
- 50 MB when you upload from a computer. From the YouTube app the limit is 2 MB for a video thumbnail and 10 MB for a podcast.
- What file format should a YouTube thumbnail be?
- JPG or PNG, the formats YouTube’s help page names for custom thumbnails.
- Why can’t I upload a custom thumbnail on YouTube?
- Custom thumbnails need a verified channel: verify it with a phone number at youtube.com/verify. YouTube also limits how many thumbnails a channel can upload each day, and Community Guidelines strikes can remove the feature for 30 days.
- Can I test two YouTube thumbnails?
- Yes. YouTube Studio on a computer can A/B test up to 3 thumbnails and titles on a long-form video, and shows the one with the most watch time to everyone. Shorts cannot be tested.
- Can SkedCast set a custom YouTube thumbnail?
- Yes. Upload a cover image to the YouTube post in SkedCast, or pick a frame from the video, and SkedCast sets it as the thumbnail right after the upload. The channel must be verified for custom thumbnails; if YouTube refuses the cover, the post says why.
Sources
Every figure on this page was checked against these pages on 4 November 2026:
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