What size is a book cover thumbnail on Amazon?

Amazon displays book cover thumbnails at approximately 90 pixels wide by 144 pixels tall in search results. This is the size most readers first see your book. If your title is unreadable and your genre is unrecognizable at this size, readers will scroll past without ever clicking.

How do I test if my book cover works at thumbnail size?

Upload your cover image to this free thumbnail tester. It will display your cover at Amazon's actual search result size (90x144 pixels) alongside larger preview sizes. Check three things: Can you read the title? Can you identify the genre? Does the main image still register? If you answer no to any of these, your cover needs adjustments before publishing.

Is this thumbnail tester free to use?

Yes, completely free. No signup, no email required. Your images are processed entirely in your browser and are never uploaded to any server. Your cover designs stay private.

Book Cover Thumbnail Tester

Most readers first see your book at 90 x 144 pixels in Amazon search results. Upload your cover and see exactly what they see.

Free. No signup. Your image never leaves your browser.

Drop your book cover here

or click to browse. JPG, PNG, or WebP.

Why the Thumbnail Test Matters

Your book cover might look stunning at full size. But most readers will never see it at full size. They will see it as a tiny thumbnail in Amazon search results, on their phone, in a BookBub email, or in a social media feed.

Amazon displays book covers at roughly 90 pixels wide by 144 pixels tall in search results. That is smaller than a postage stamp on most screens. At that size, intricate details vanish. Thin fonts disappear. Low-contrast designs turn into blurry rectangles.

The covers that sell are the ones that work at every size. They are designed with the thumbnail in mind from the start, not as an afterthought. Bold titles, high contrast, clear focal points, simple compositions.

This tool shows you exactly what readers see. No guessing, no squinting at your screen. Upload your cover, check the sizes, run the checklist.

How to Fix a Cover That Fails

Increase font size

Your title should fill at least a third of the cover width. If it looks "too big" at full size, it is probably right for thumbnail.

Use bolder weights

Thin and light font weights vanish at small sizes. Go bold or extra-bold for your title text.

Maximize contrast

Light text on dark backgrounds or dark text on light backgrounds. Avoid placing text over busy image areas.

Simplify composition

One clear focal point. Remove secondary elements that muddy the thumbnail. Less is more at small scale.

Limit your palette

Two to three dominant colors. Too many colors create visual noise that turns into mush at thumbnail size.

Check your genre cues

Readers should recognize the genre instantly. Dark palette for thrillers, script fonts for romance, bold sans-serifs for non-fiction.

Frequently Asked Questions

Amazon displays book cover thumbnails at approximately 90 pixels wide by 144 pixels tall in search results. This is the size most readers first see your book. On mobile devices the thumbnail may be even smaller. If your title is unreadable at this size, readers scroll past without ever clicking through to the product page.

No. This tool runs entirely in your browser using JavaScript. Your cover image is processed locally on your device and is never uploaded, stored, or sent anywhere. Your designs stay completely private.

JPG, PNG, and WebP. These are the standard formats used for book covers. If your cover is in a different format (like TIFF or PSD), export it as JPG or PNG first from your image editor.

Yes, or at least keep the thumbnail in mind from the start. Some designers create the thumbnail version first and scale up. At minimum, test the thumbnail before you finalize any cover. If you design a beautiful full-size cover that fails at thumbnail scale, you have designed a cover that does not work where it matters most.

The most common fixes are: increase your title font size, switch to a bolder weight, raise the contrast between text and background, simplify the composition, and reduce the color palette. Our full guide on the thumbnail test walks through each fix with real examples.

The Thumbnail Is Step Four

Testing your thumbnail is the final checkpoint. The Art Director Method teaches you the full 4-step process that gets you here: from interviewing your story to directing AI to executing a cover that works at every size.

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