YouTube Thumbnail Tester
See your thumbnail where people will meet it: next to other videos, with your title, channel and the time label on top. Compare up to three versions side by side, check size, shape and file against YouTube Help, and download the mock-up as an image.
- Free
- No sign-up
- Runs in your browser
Someone shared this result with you. It was made with YouTube Thumbnail Tester, free on VISU, no sign-up.
Mock-up
Add a thumbnail, or use the example, to see it in the list.
Unofficial mock-up with generic boxes. Real YouTube layouts change with the device, the app version and tests, so use this to compare, not as an exact copy.
At phone size
Each version at 168 pixels wide, about the size of a thumbnail in a list on a phone. If the idea does not read here, simplify it.
Estimate what the views could pay with your own RPM, or put your numbers on a media kit for brands.
YouTube money calculator Media kit generatorWhat YouTube asks for
From YouTube Help, read on October 16, 2026. The checks above use these numbers and nothing else.
| Shape | 16:9 for videos (9:16 for Shorts). |
|---|---|
| Size | 3840 x 2160 recommended, at least 640 pixels wide. |
| Format | Image formats such as JPG or PNG. |
| File size | 2 MB from a phone, 50 MB from a computer. |
| Account | Uploading your own thumbnail needs a verified account. |
VISU is not affiliated with YouTube or Google. YouTube is a trademark of Google LLC.
Promoting your channel off YouTube?
VISU Ads runs ads on QR codes, push notifications and VISU Link pages, with VISU Credits for the people who watch. It does not place ads inside YouTube.
See VISU AdsHow to use it
- Drop one to three thumbnails. They stay in your browser.
- Type the video title, your channel name, the views, the age and the length the way you want them to appear.
- Switch between the home grid, search results, up next and the phone feed, in light and dark.
- Read the checks under the mock-up, look at the phone size preview and download or share the picture.
Examples
Picking between two ideas
Two thumbnails for the same video with one shared title, side by side in the home grid. The letters A and B make it easy to ask a friend which one they would click.
Checking an old 4:3 image
A 4:3 picture shows up with black bars on both sides. Switching to "Crop to fill" shows what is lost at the top and the bottom.
Making sure the text reads
At phone size the long line of small words disappears. The time label also covers the last word, so the text moves to the left.
Add this tool to your site
Put this tool on your blog, store or club site. It runs inside your page, free, with no account, and a small "by VISU" credit line under it.
Questions
What size should a YouTube thumbnail be?
YouTube Help recommends 3840 x 2160 pixels for videos, with a minimum width of 640 pixels, and a 16:9 shape. The page is linked below with the date it was read.
Which file formats and file sizes work?
YouTube Help names image formats such as JPG or PNG. The file limit is 2 MB when you upload from a phone and 50 MB from a computer. Other formats are marked "check" here because the help page does not name them.
Is this the real YouTube layout?
No. It is an unofficial mock-up with generic grey boxes and no logo. Real layouts change with the device, the app version and the tests YouTube runs, so use it to compare versions, not as an exact copy. VISU is not affiliated with YouTube.
Are my thumbnails uploaded anywhere?
No. The images are opened and drawn in your browser. They are not sent, saved or written into the page address, and neither are the titles you type.
Why highlight the bottom right corner?
In the lists people browse, the length of the video sits in a small dark label over that corner. A face, a price or a key word placed there can end up hidden.
Why can I not upload a custom thumbnail on YouTube?
YouTube Help says that uploading your own thumbnail needs a verified account. Until then you can choose one of the suggestions YouTube generates.