YouTube Thumbnail Tester
Upload your YouTube thumbnail and instantly see how it looks at four real-world sizes — from the full 1280 × 720 watch page down to the tiny 120 × 68 row used on mobile. Toggle between dark and light backgrounds to make sure your thumbnail works on both YouTube themes, and add a title overlay to preview how YouTube’s gradient and text will sit on top of your image.
How to use
- 1
Upload your thumbnail
Drop a JPG, PNG or WebP. The recommended size is 1280 × 720px (16:9 aspect ratio). Other sizes will load but YouTube will resize or crop them.
- 2
Enter a title overlay
Type the video title exactly as it will appear on YouTube. The overlay uses the same dark-to-transparent gradient and bottom-left alignment YouTube uses for video cards.
- 3
Switch background theme
Use the Dark / Light toggle to see your thumbnail on both YouTube themes. A thumbnail that pops on dark may disappear on light, and vice versa.
- 4
Inspect every size
Scroll through the full, medium, small and tiny previews to confirm that key text and faces stay legible at the smallest size — that’s where most clicks are decided.
Common use cases
- Verify your thumbnail text is readable at 120 × 68 before publishing.
- Check whether your thumbnail still pops on YouTube’s light theme.
- Test how the YouTube title gradient affects legibility of your image.
- Confirm your image is the ideal 1280 × 720 before upload so YouTube doesn’t crop it.
Limitations
- The title overlay mimics YouTube’s standard card style; the actual watch-page placement and font may differ slightly.
- YouTube sometimes A/B-tests thumbnail crops (especially the very small mobile rows), so always verify on a real device after publishing.
- The character counts at which YouTube truncates titles vary by language, device and layout — the tool uses the common English thresholds.
- Custom thumbnails must be uploaded separately in YouTube Studio after your channel reaches the verification threshold.
Frequently asked questions
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