YouTube Thumbnail Preview & Safe-Zone Checker
Check technical requirements and see how your thumbnail reads in compact YouTube surfaces—without uploading it.
Choose a thumbnail
The image stays on this device and is never uploaded.
Small-screen preview
Check readability and the duration safe zone.
How the calculator works
Select a local JPG, PNG, or WebP. The browser checks its pixel dimensions, aspect ratio, and file size, then creates temporary previews at large and compact sizes.
The image is represented by a temporary Object URL that is released when you replace it or leave the page.
1280 × 720 · 16:9 · up to 2 MBKeep important text and faces away from the bottom-right duration badge.
Frequently asked questions
Does this tool upload my thumbnail?+
No. The image stays in your browser and is never uploaded, stored, or included in analytics.
What thumbnail size should I use?+
Use a 16:9 image at least 1280 by 720 pixels in JPG, PNG, or WebP format and keep the file at or below 2 MB.
Why preview a thumbnail at a small size?+
Most viewers see thumbnails in compact feeds. A small preview helps reveal text and details that become unreadable after scaling.