YouTube Thumbnail Previewer
Preview how your YouTube thumbnail looks across devices before you upload.
The YouTube Thumbnail Previewer shows how your thumbnail will look in real YouTube layouts — desktop suggested videos, the mobile feed and small dark-mode sizes — so you can catch unreadable text before you ever upload.
Why use this tool
Real-context mockups
See your thumbnail in desktop, mobile and dark-mode layouts.
Small-size check
Confirms your text stays readable at the size most viewers see.
Upload or paste a URL
Use a local image file or an existing thumbnail URL.
How to use it
Add your thumbnail
Upload an image or paste a thumbnail URL.
Review the previews
Check it across desktop, mobile and dark mode.
Fix and re-test
Adjust text and contrast until it reads at every size.
Frequently asked questions
What size should a YouTube thumbnail be?+
1280×720 pixels with a 16:9 ratio is recommended, under 2MB.
Why preview at small sizes?+
Most viewers first see thumbnails small on mobile — text that's clear large can vanish small.
Is my image uploaded anywhere?+
No. The preview is rendered entirely in your browser; nothing is sent to a server.
Can I preview an existing video's thumbnail?+
Yes. Paste its thumbnail URL (for example from img.youtube.com) to preview it.