YouTube Thumbnail Tester — See Your Thumb at Feed Sizes

How to use

1. Load a thumbnail image (stays on your device).
2. Type the video title to overlay on every mock card.
3. Read the sidebar, mobile, suggested-row and 1280×720 previews.
4. Check the 2 MB and 1280×720 verdict line before uploading.

About this tool

Most thumbnails are judged at postage-stamp size, so test them where they actually live. Load an image and this page renders a faithful mock YouTube layout: the desktop sidebar card at 360×202, a small mobile card, and a suggested-videos row — all center-cropped the way the platform crops them. Type your title underneath and judge whether it stays readable next to the art at each size, which is the real test of a thumbnail. The tool also shows a native 1280×720 preview and flags the two checks that matter: file size against YouTube's 2 MB limit, and whether your image genuinely reaches 1280×720 at 16:9. Your image is read locally with FileReader and never uploaded. Your file never leaves this page — processing runs entirely in your browser; nothing is uploaded and the data is dropped from memory when you close the tab.

FAQ

Rate this tool

Your rating stays in this browser (local storage) — nothing is sent to any server.