YouTube thumbnail size checker
Check local image dimensions, ratio and file size against the current YouTube guidance for your upload device.
Current YouTube guidance
Recommended video resolution: 3840 × 2160. Shorts: 2160 × 3840. Minimum video width: 640 pixels; minimum Shorts height: 640 pixels. Use 16:9 for video and 1:1 for podcast playlists.
Mobile upload: under 2 MB for video or 10 MB for podcasts. Desktop: under 50 MB for video, Shorts and podcasts. The source does not give a separate mobile Shorts limit, so this checker will not invent one.
Size checks do not prove that an image will get clicks or that YouTube will accept the upload. Video thumbnails can also depend on account verification and content rules.
YouTube official thumbnail guidance (checked 14 Oct 2026)