YouTube thumbnail size and rules
Your thumbnail is the first thing people judge before they click. YouTube’s current guidance is to aim high on resolution so thumbnails look sharp on big TVs and small phones alike.
| Rule | Videos | Shorts |
|---|---|---|
| Recommended size | 3840 × 2160 px | 2160 × 3840 px |
| Minimum | 640 px wide | 640 px tall |
| Aspect ratio | 16:9 | 9:16 |
| Formats | Common image formats such as JPG or PNG | |
| File size limit | 50 MB uploading on desktop; 2 MB for video thumbnails on mobile | |
Tips for thumbnails that get clicks
- Keep text short and big enough to read on a phone screen.
- Leave the bottom-right corner clear, where the video length often appears.
- Use strong contrast between the subject and the background.
- Check how it looks small: if it still reads at phone size, it will work everywhere.
What we check
The checker reads your image in your browser and compares it with YouTube’s published rules:
- Format: JPG or PNG passes; other formats get a warning.
- Minimum size: at least 640 px wide for videos, 640 px tall for Shorts.
- Shape: within 1% of 16:9 for videos or 9:16 for Shorts.
- Sharpness: whether it reaches the recommended 3840 × 2160 px (or 2160 × 3840 px for Shorts).
- File size: under 2 MB works everywhere; up to 50 MB works when uploading from a computer.
Source: YouTube Help — Add video thumbnails on YouTube. Rules reviewed November 2026.
Common questions
What is the best YouTube thumbnail size?
YouTube recommends 3840 × 2160 pixels for video thumbnails (16:9) and 2160 × 3840 for Shorts (9:16).
What is the minimum thumbnail size?
Video thumbnails must be at least 640 pixels wide, and Shorts thumbnails at least 640 pixels tall.
Why won’t my thumbnail upload from my phone?
On mobile, video thumbnails are limited to 2 MB. Compress the image or upload it from a computer, where the limit is 50 MB.
Is my image uploaded anywhere?
No. The checker reads the image inside your browser and nothing leaves your device.