YouTube Thumbnail Tester
Drop in a thumbnail and see it at the three sizes YouTube actually displays — including the 168-pixel one where most detail disappears.
Home feed
the widest — two lines of titleSearch results
larger text, thumbnail on the leftSuggested sidebar
the narrowest — where titles get cut100% freeNo account requiredNo usage limit
How it works
- 01
Upload your thumbnail
Or paste a YouTube link to load an existing one and compare against it.
- 02
Add the title it ships with
A thumbnail is never seen alone. Judging it without its title is judging the wrong thing.
- 03
Check the smallest size
At 168 pixels wide, small text vanishes and busy images turn to mush. That is the real test.
What people use it for
Testing readability when small
Text that looks bold at full size often disappears in the sidebar. This is the fastest way to catch it.
Comparing against a competitor
Load their thumbnail, then yours, and see which one holds up next to the other.
Checking title and image overlap
If the thumbnail says the same thing as the title, one of the two is wasted.
Frequently asked questions
What size should a YouTube thumbnail be?+
1280×720 pixels, 16:9, under 2 MB, in JPG, PNG, GIF or WEBP. That is the upload spec — but it is almost never the display size. YouTube scales it down to as little as 168 pixels wide, which is what this tool shows you.
Is my thumbnail uploaded to your server?+
No. It is read locally in your browser and never sent anywhere. Nothing is stored or logged — which is why there is no account and no usage limit.
How much text should a thumbnail have?+
Three to five words is the usual advice, and the reason is visible here: at sidebar size, anything longer becomes unreadable. If you cannot read it in the smallest preview, viewers cannot either.
Do faces really perform better?+
Faces attract attention reliably, which is why they are everywhere. But when every thumbnail in a niche has a shocked face, the face stops being the differentiator and becomes the wallpaper.
Can I A/B test thumbnails on YouTube?+
Yes, YouTube has a built-in test feature for eligible channels that runs up to three variants and picks a winner on watch time. This tool is for the step before that: not publishing something you would not have chosen once you saw it small.
Why does my thumbnail look different on YouTube?+
Compression. YouTube re-encodes every thumbnail, and fine gradients or thin text suffer most. Designing with strong contrast survives that process; subtle work does not.
Related tools
All tools →Spot the videos breaking out before they reach your market
VideoTrends measures every channel you follow against its own baseline, every two hours, and surfaces the videos that overperform.
Start free