YouTube thumbnail tester

YouTube thumbnail tester features

• 01

  Four real YouTube layouts

  See your thumbnail in the desktop search result, the sidebar up-next rail, the mobile home feed and the 2-up browse grid. Small sizes are where most clicks are decided — this is where you catch the issue.

• 02

  Title, channel, views, theme

  Fill in the title, channel name, view count, upload time and duration badge so the mockup mirrors your real card. Toggle light and dark theme to see which version actually reads.

• 03

  Fully private preview

  Your thumbnail never leaves the browser. Handytool renders everything locally with the HTML5 Canvas API — no upload, no account, no server.

YouTube thumbnail tester FAQ

What size should a YouTube thumbnail be?

YouTube recommends 1280×720 pixels (16:9) with a minimum width of 640 pixels, saved as JPG, PNG or GIF under 2 MB. The tester warns you if your upload is the wrong aspect or under-sized.

Why does my thumbnail look unreadable in the mobile preview?

On phones, YouTube renders thumbnails as small as 168 pixels wide. Small faces, thin text and low-contrast backgrounds disappear at that size. The tester exposes this before you publish — if you can't read the title at mobile-feed scale, the thumbnail needs more contrast and bigger key elements.

Does this tool upload my thumbnail anywhere?

No. The image is rendered entirely in your browser using Canvas. Handytool never receives, stores or sees the thumbnails you preview.

Can I test both light and dark mode?

Yes. Switch the theme toggle to preview how your thumbnail reads on YouTube's light background vs the dark UI. Bright whites look different on each — this catches accidental halos and washed-out text.

Does it work for YouTube Shorts?

This tool previews the standard 16:9 thumbnail used on video pages, search and home. Shorts use a vertical 9:16 cover pulled from the video itself, so a separate Shorts preview isn't needed.