YouTube thumbnail tester
Upload your thumbnail and type your title. The tester shows them the way YouTube does: in the home feed, in search results, in the suggested videos sidebar and on a phone. Paste links to other videos in your niche to see yours next to them. Upload up to three versions to switch between them. Your image stays in your browser.
What to look for
- The sidebar. Suggested videos show thumbnails at 168 × 94 pixels. If the text or the face doesn't read at that size, it won't read on most phones either.
- The title cut-off. YouTube cuts titles to two lines. Check that the words that matter come before the cut.
- The neighbours. A thumbnail that looks bold on its own can disappear among others with the same colours. If every video in your niche is red and yellow, try blue.
- Light and dark mode. A dark thumbnail with no border can melt into the dark theme.
- The length badge. It covers the bottom-right corner. Keep text and faces out of that spot.
Comparing versions
Upload two or three versions and click between them. Pick the one you notice first when you glance at the page. Once the video is live, YouTube's Test & compare in Studio can test up to three thumbnails on real viewers, and the CTR calculator shows what a better click-through rate is worth.
Other videos in the preview
The titles, channel names and thumbnails of the links you paste come from YouTube's public oEmbed endpoint and image server. Empty slots are grey placeholders.
Size and format
Upload a 16:9 image, ideally 1280 × 720. If yours is a different size, the thumbnail resizer crops or fits it. To score the design itself, try the thumbnail rater.
Common questions
How do I preview a thumbnail before uploading?
Upload it here with your title and see it in the home feed, search, the sidebar and on a phone, next to real videos you paste in.
Can I compare thumbnail versions?
Yes. Upload up to three and click between them. Once the video is live, test them on real viewers with YouTube's A/B testing.
Is the thumbnail uploaded?
No. The preview is built in your browser.
What size should my thumbnail be?
16:9, ideally 1280 × 720 or larger. The thumbnail resizer fixes other sizes.