YouTube thumbnail rater
Upload a thumbnail and the rater scores it out of 100 on four things that make thumbnails readable in a busy feed: contrast, colour, faces and text. It also shows the image at sidebar and phone size. Everything runs in your browser: face and text detection use open-source models (MediaPipe and Tesseract) downloaded once, and your image isn't uploaded.
How each score works
| Score | What it measures |
|---|---|
| Contrast | How far apart the light and dark parts of the image are. Flat, grey images score low. |
| Colour | How saturated and varied the colours are, using the Hasler–Süsstrunk colourfulness measure. |
| Face | Whether there's a face, and how much of the image the largest one covers. |
| Text | How many words it finds and how tall the smallest one is. Short, big text scores high. |
The overall score is the average of the four. It's a quick check, not a prediction of clicks: a minimal, muted thumbnail can still work if everything around it in your niche is loud.
A thumbnail without a face
That's fine. Product reviews, tutorials and scenery often do better without one. With no face, the face score sits at 50 and only pulls the average down a little.
Text that the rater can't read
The text check uses OCR, so it finds plain, printed words best. Heavy outlines, 3D effects or handwriting may not be detected. If the rater finds no text but you added some, view the small previews: if you can't read it there, viewers can't either.
Next steps
Put the thumbnail next to real videos with the thumbnail tester, make sure it's 1280 × 720 with the thumbnail resizer, and after publishing track the result with the CTR calculator.
Common questions
How is the thumbnail score worked out?
It averages four scores out of 100: contrast, colour, face and text, each measured in your browser.
Is a high score a guarantee of clicks?
No. It's a readability check. A muted thumbnail can still win in a niche where everything else is loud.
Is my thumbnail uploaded?
No. Face and text detection run in your browser with open-source models.
What should I do after rating it?
Preview it next to real videos with the thumbnail tester, then track the result with the CTR calculator.