YouTube · thumbnails · Shorts
YouTube thumbnail size checker.
Enter your thumbnail’s pixel size (and file size if you like). The tool checks it against the numbers on YouTube’s help page and shows the crop that fixes the ratio. Runs in your browser; nothing is uploaded.
Your thumbnail
Result
Fill the form and press Check.
Worked example
A 1920 × 1280 image for a video is 1.5 to 1, not 16:9 (1.778 to 1). The 16:9 crop is 1920 × 1080. Scaling that up to YouTube’s recommended 3840 × 2160 is 200% of the cropped size, so a larger source gives a sharper result. Width 1920 clears the 640 px minimum.
How it works
YouTube’s help page ("Add custom thumbnails on YouTube", opened 8 October 2026) says to use a custom thumbnail as large as possible; it recommends 3840 × 2160 pixels for videos and 2160 × 3840 for Shorts, with a minimum width of 640 pixels for videos and a minimum height of 640 pixels for Shorts. Use an image format such as JPG or PNG. Limits depend on the device: mobile 2 MB for video thumbnails (10 MB for podcasts) and desktop 50 MB. Aim for 16:9 for videos and 9:16 for Shorts, and 1:1 for podcast playlists.
The page also notes that vertical videos with a 16:9 custom thumbnail are replaced by an auto-generated 4:5 thumbnail on the home, explore and subscription pages. The ratio check allows 0.5% tolerance. YouTube changes these numbers, so check the help page before you rely on them.
Source, opened 8 October 2026: Add custom thumbnails on YouTube - YouTube Help. Sizes on this page have changed over time, so treat the numbers here as current only as of that date.
FAQ
What size is a YouTube thumbnail?
YouTube Help recommends 3840 × 2160 pixels for video thumbnails (16:9) and 2160 × 3840 for Shorts (9:16), with a minimum width of 640 px for videos and a minimum height of 640 px for Shorts.
What is the YouTube thumbnail file size limit?
On mobile the limit is 2 MB for video thumbnails (10 MB for podcasts). On desktop it is 50 MB for video, Shorts and podcast thumbnails.
What aspect ratio should a YouTube thumbnail be?
16:9 for videos, 9:16 for Shorts and 1:1 for podcast playlists, according to YouTube Help.
What file type can I use?
YouTube Help lists image formats such as JPG or PNG.
Do the sizes change?
Yes. YouTube updates its help pages, so confirm on the linked page before a big upload.
Disclaimer
Reflects YouTube’s published help page as opened on the date shown. Not affiliated with YouTube or Google. Thumbnails must also follow YouTube’s Community Guidelines.