YouTube Thumbnail Size Checker
YouTube's recommended thumbnail size is 3840×2160 pixels, at a 16:9 aspect ratio, as a JPG or PNG. The image must be at least 640 pixels wide. Drop your thumbnail below to check it against every rule, for a video or a Short. It runs in your browser, so your image never leaves your device.
YouTube thumbnail size requirements
These are the rules on YouTube's help page for custom video thumbnails, as of November 2026, and the ones the checker below tests.
| Video thumbnail | Shorts thumbnail | |
|---|---|---|
| Recommended size | 3840×2160 pixels | 2160×3840 pixels |
| Minimum | 640 pixels wide | 640 pixels tall |
| Aspect ratio | 16:9 | 9:16 |
| File size | Up to 50MB from a computer, 2MB from the YouTube app | Up to 50MB (added from a computer only) |
| Format | JPG or PNG | JPG or PNG |
- At least 640 pixels wide
- 16:9 aspect ratio
- 1280×720 or larger (3840×2160 recommended)
- Under 50MB (2MB from the YouTube app)
- JPG or PNG
How to check your thumbnail size
- Choose Video thumbnail or Shorts thumbnail.
- Drop your image on the box, choose it from your device, or paste a copied image or screenshot.
- Read each rule. Green means it passes. Amber means YouTube takes it but shows it worse, such as with black bars. Red means YouTube won't take it.
- Fix what isn't green. "Resize to 16:9" opens the thumbnail resizer with your image already loaded. For a small image, export a larger copy from your source: enlarging it won't add detail.
1280×720, 1920×1080 or 3840×2160?
All three are 16:9 and all three pass. YouTube asks for a thumbnail "as large as possible" because TVs show it big, so export at the largest 16:9 size your source really has, and never go below 1280×720: under it, an A/B test drops every thumbnail in the test to 480p. Upscaling a small image makes a bigger file, not a sharper picture. The YouTube thumbnail size guide explains which size to export for each source, and crop or black bars shows what happens to an image that isn't 16:9.
Before you upload
The right size is only the start. See it the way viewers will: preview your thumbnail on YouTube beside real videos on the home page, in search and on mobile, or get an AI critique of it. If YouTube still refuses the file, here is why a thumbnail upload fails. Need the thumbnail of a video that is already up? The YouTube Thumbnail Downloader pulls every size.
Frequently asked questions
What size is a YouTube thumbnail?
YouTube recommends 3840×2160 pixels at a 16:9 aspect ratio, at least 640 pixels wide, as a JPG or PNG. The file can be up to 50MB from a computer, or 2MB from the YouTube mobile app. 1280×720 also meets every requirement.
Is 1280×720 still OK?
Yes. It meets every requirement, and it is the smallest size an A/B test takes without YouTube dropping every thumbnail in the test to 480p. A larger thumbnail only looks sharper on big screens, and only if your source has that much detail.
What is the maximum file size for a YouTube thumbnail?
50MB when you upload from a computer, and 2MB from the YouTube mobile app. Shorts thumbnails can only be added in YouTube Studio on a computer, so their limit is 50MB.
Why does my thumbnail have black bars on YouTube?
It isn't 16:9. YouTube doesn't stretch an image of another shape: in most places it shrinks it into the 16:9 frame with black bars around it, and a phone's channel page crops it instead. Resize it to 16:9 before you upload, so you choose what fills the frame.
What size is a YouTube Shorts thumbnail?
YouTube recommends 2160×3840 pixels at 9:16, at least 640 pixels tall. 1080×1920 is the same shape and also fine. Custom Shorts thumbnails can only be added in YouTube Studio on a computer.
Does DPI matter for a YouTube thumbnail?
No. A thumbnail has no size in inches or centimeters. Saving it at 72 or 300 DPI changes nothing on YouTube: only its width and height in pixels count.
Is my image uploaded?
No. The checker reads your file in your browser and sends it nowhere. Only an AI critique, if you ask for one, uploads the image to analyse it.