YouTube Thumbnail Tester

About YouTube Thumbnail Tester

Why you need to test thumbnails at small sizes

Over 70% of YouTube watch time happens on mobile. On a phone, your thumbnail is rendered at roughly 210×118 pixels — smaller than a postage stamp. If your text isn't legible and your face isn't recognizable at that size, viewers will scroll past.

Our YouTube Thumbnail Tester shows your thumbnail at the actual pixel sizes YouTube uses across devices: mobile feed (210×118), desktop search (246×138), sidebar suggestion (168×94), notification (120×68), and TV (1280×720).

How to use the tester

1. Upload your thumbnail (any image format) OR paste a YouTube URL to load an existing video's thumbnail
2. Scroll through the preview cards showing each display size
3. Verify text is legible at the smallest sizes (120×68 notification is the toughest test)
4. Check face visibility — faces should be recognizable at 168×94
5. Redesign if needed — make text bigger, simplify the composition, increase contrast

Design for the smallest size first

A common mistake is designing a thumbnail at full 1280×720 size and assuming it'll look good everywhere. It won't. Design for the smallest size first — if it works at 120 pixels, it'll work everywhere.

Tips for small-size legibility:

• Limit text to 3-5 words — long sentences become illegible
• Use high contrast — white text on dark background or vice versa
• Make faces large — at least 30% of the frame
• Avoid thin fonts — they disappear at small sizes

Once your thumbnail passes the test, resize it to 1280×720 and upload it to YouTube.