YouTube Thumbnail Previewer

YouTube displays thumbnails at dramatically different sizes depending on where they appear:

Mobile home feed: Approximately 168 x 94 pixels. This is the smallest, most common display context and the one most creators fail to design for.

Desktop homepage grid: Around 320 x 180 pixels. Larger than mobile, but still significantly smaller than your design canvas.

Suggested/recommended panel (sidebar): Approximately 246 x 138 pixels. This is the view that drives a huge percentage of views - "Up Next" suggestions after another video ends.

Search results: Around 240 x 135 pixels on desktop. Mobile search is even smaller.

Watch page (below the player): On desktop, related video thumbnails appear at roughly 168 x 94 pixels.

The thumbnail you design at 1280 x 720 pixels looks completely different at 168 x 94. Text that's readable at full size becomes illegible. Faces that are expressive at full size become unrecognizable. Color details that pop at full size merge together.

This tool removes the guesswork by showing you the preview at all these sizes simultaneously.

Rule 1: Text should be readable at 168x94 pixels. If you're adding text overlay to your thumbnail, it needs to be large enough (and high-contrast enough) to read at the smallest display size. Use 60-80pt font minimum at 1280x720. High contrast: white text on dark backgrounds, or dark text on bright backgrounds.

Rule 2: No more than 6 words of text. At small sizes, long text becomes unreadable. Keep text overlay to a short, punchy phrase: "I was WRONG," "Don't do this," "My honest review." Less is more, especially at thumbnail display sizes.

Rule 3: Face expressions need to read at distance. If your thumbnail features a face, the expression needs to be clearly legible at 168x94. Subtle expressions - a slight smile, mild surprise - don't read at that size. Exaggerated expressions - wide eyes, open mouth, shock, laughter - do.

Rule 4: One focal point, not three. Thumbnails with too many visual elements competing for attention fail at small sizes. Pick one thing to focus attention on: the face, the product, the result, the text. Everything else is supporting context.

Here's a specific experiment worth trying on your lowest-performing video:

• Upload your current thumbnail into this previewer. Look at the smallest size. What's wrong?
• Open your design tool. Redesign the thumbnail with larger text, simpler composition, and higher contrast.
• Preview the new version here at all sizes. Is it better?
• If yes, swap it in YouTube Studio.
• Check CTR at 48 hours.

MrBeast's team reportedly runs this exact type of test iteration on major videos. They A/B test between two thumbnails, keep the winner, and sometimes run 3-4 rounds of testing.

You don't need to run 4 rounds. Just test one redesign on your lowest-CTR video this week and see what happens. The data will tell you whether the change worked. This previewer is the first step in that process.