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YouTube thumbnail preview

A thumbnail can look great in your design tool and still get lost in a busy feed, and a long title gets cut off. See yours on YouTube's home page, in search, beside a playing video, and on a phone, in light and dark. Compare up to three thumbnails. Your images never leave your device.

  • Free
  • No sign-up
  • Runs in your browser

YouTube thumbnail preview

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Runs in your browser. Nothing you add leaves this page.

Three steps

How it works

  1. Add your thumbnail, or up to three to compare. Or try the sample.

  2. Type your title, channel name, views, upload age, and video length.

  3. Switch layouts and themes to see how each thumbnail stands out and where the title gets cut.

GuideReviewed

How to check a YouTube thumbnail and title before you publish

Contents

YouTube's thumbnail requirements

These come from YouTube's help page on custom thumbnails, checked in October 2026. The file size limits are firm and YouTube asks for a minimum width; the size, shape, and format are its recommendations.

  • Size: 3840 × 2160 pixels, and at least 640 pixels wide.
  • Shape: 16:9 for regular videos. Shorts thumbnails are 9:16, at 2160 × 3840.
  • Format: JPG or PNG.
  • File size: up to 2 MB from the YouTube app on a phone, or 50 MB from a computer.
  • Account: custom thumbnails need a verified YouTube account.

Why your title gets cut

YouTube allows titles of up to 100 characters, but most layouts show only part of that. On the desktop home page and in search, a title gets two lines; beside a playing video, three; on a phone, two. Anything longer ends in an ellipsis.

The preview wraps your title at the sizes YouTube used on October 18, 2026, and lists the words each layout hides. Treat the breaks as close estimates: screen sizes, fonts, and YouTube's own design tests move them a little.

Make the thumbnail readable at every size

In a 1440-pixel-wide browser window, the same image shows about 347 pixels wide on the home page, 500 in search, and 218 beside a playing video. Big shapes, a few large words, and strong contrast survive the smallest size; fine detail and small text don't.

YouTube shows the video length in the bottom-right corner of the thumbnail, so keep faces, logos, and words away from it. Check the dark theme too: a thumbnail with dark edges can blend into a dark page.

Compare thumbnails before you publish

Add up to three thumbnails to see them side by side in every layout, labeled A, B, and C, each with its own checks. Pick the one that reads fastest at the smallest size.

Once the video is live, YouTube Studio on a computer can test up to three titles and thumbnails with real viewers and keep the one with the most watch time.

Questions, answered

What people ask before they use the YouTube thumbnail preview.

No. The preview runs entirely in your browser. Your images are opened and shown on your device and never sent to a server.

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From Ampere

Thumbnail checked. Now make the next one.

Ampere is an AI marketing agent that creates YouTube thumbnails, scripts, hooks, and captions from your saved Brand memory, ready for your review.

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