How to test a thumbnail and title
- Load your thumbnail. The tool checks the size, the 16:9 ratio and the 2 MB file limit.
- Type the title exactly as you’ll publish it. It is cut to two lines the way YouTube cuts it.
- Switch between Home, Search, Mobile and Sidebar, and between light and dark mode.
- Load a second version as Thumbnail B to compare both in the same feed, then turn on the squint test to see which one still reads when blurred.
YouTube thumbnail specs
| Spec | Requirement |
|---|---|
| Recommended size | 1280 × 720 px |
| Minimum width | 640 px |
| Aspect ratio | 16:9 |
| Maximum file size | 2 MB |
| Formats | JPG, PNG, GIF (not animated) |
What makes a thumbnail work at small sizes
- One clear subject. A face with a readable expression or a single object beats a busy scene.
- Three or four words at most, in a heavy font. Anything smaller turns into noise in the sidebar.
- Strong contrast against both the white and the dark YouTube backgrounds.
- Keep the bottom-right corner clear, where the video duration covers part of the image.
- Let the title and the thumbnail say different things. Repeating the title in the image wastes space.
Making your thumbnail the right size first? The social image resizer crops any picture to 1280 × 720.
Last reviewed October 2026.
Frequently asked questions
What size should a YouTube thumbnail be?
1280 × 720 pixels, a 16:9 ratio, under 2 MB, as JPG, PNG or GIF. The preview checks your file against those specs when you load it.
How long can a YouTube title be?
Up to 100 characters, but feeds show only two lines. That is usually 60 to 70 characters on desktop and fewer on mobile. The preview cuts the title the way YouTube does so you can read what viewers actually see.
Can I compare two thumbnails?
Yes. Load a second version and it appears in the same mock feed next to the first, so you can judge which one stands out at the same size.
Why does my thumbnail look good large but weak in the feed?
Most clicks happen at small sizes: the mobile feed, search and the suggested sidebar. Thin text and busy details disappear there. Check the sidebar view, where the thumbnail is only about 168 pixels wide.
Is my thumbnail uploaded?
No. The image is opened locally by your browser and is never sent to a server, so you can test unreleased designs.
Is this the real YouTube interface?
No. It is an independent mock-up that reproduces the sizes and title truncation of YouTube layouts. It is not affiliated with YouTube.