Free browser tool
Free YouTube Thumbnail Tester
Check your thumbnail and title before you publish. Drop in your image, type your title, and see a thumbnail preview at real feed sizes: home, search, sidebar, mobile, and the tiny notification size. Compare up to three thumbnails side by side.
Loading the thumbnail tester… If this message stays here, refresh the page and check that JavaScript is enabled.
1. Add your thumbnail
2. Type your title
The length badge sits on the bottom-right corner of every thumbnail. Keep important text away from it.
3. Check the preview
Illustrative YouTube-style layouts, sized like common views. Real layouts vary by screen and change over time. Not affiliated with YouTube or Google.
Happy with it? Plan the video behind this thumbnail in ScreencastKit: title options, a section-by-section script, a screen recorder, and a ready-to-upload publish pack. Start a free project →
A YouTube thumbnail preview that shows what viewers see
You design thumbnails at 1280 × 720, but almost nobody sees them that big. On the home feed a thumbnail is about 360 pixels wide. In the up-next sidebar it is 168. In notifications it is barely more than a stamp. This thumbnail tester puts your image at those sizes, next to your title, so you can tell at a glance whether the words are readable and whether the image stands out.
How to test a YouTube thumbnail
- Add your thumbnail. Choose, drop, or paste a JPG, PNG, WebP, or GIF. Add up to three versions to compare.
- Type your title. The preview updates as you type and shows which words get cut off on each layout.
- Check every size and the feed. Switch between dark and light mode, then view your thumbnail among placeholder videos to see whether it stands out.
YouTube title checker: why titles get cut off
YouTube accepts titles up to 100 characters, but feeds show about two lines. Wide letters like W and M use more space than narrow ones like i and l, so a character count alone can't tell you where the cut falls. The tester wraps your title the way a browser does at each layout's width and lists any hidden words. Put the words that earn the click first.
What makes a thumbnail readable at small sizes
- Use three to five large words, or none. Small text disappears at sidebar size.
- Use strong contrast between text and background, and check both dark and light mode.
- Keep faces and key details away from the bottom-right corner, where the length badge sits.
- Let the thumbnail and title work together instead of repeating the same words.
YouTube thumbnail tester questions
Does this upload my thumbnail?
No. Your image is read and displayed by your browser only. Nothing is uploaded to our servers or any other service, and closing the tab clears it.
What size should a YouTube thumbnail be?
Use 1280 × 720 pixels (16:9), at least 640 pixels wide, as a JPG, PNG, or GIF under 2 MB. The tester warns you if your image is the wrong shape, too small, or over 2 MB.
How long can a YouTube title be before it gets cut off?
YouTube allows 100 characters, but feeds show about two lines. Depending on letter widths, that is often 50 to 70 characters on the home feed and fewer in the sidebar. The tester shows exactly which words are hidden on each layout.
Are these the exact YouTube layouts?
No. They are illustrative layouts sized like common YouTube views. YouTube changes its design and sizes vary by screen, so treat the preview as a readability check, not a pixel-perfect copy. This tool is not affiliated with YouTube or Google.
Can I test a thumbnail from a video that's already published?
Download it from your own YouTube Studio or use your original design file, then add it here. The tester only works with image files from your device.