YouTube Thumbnail Previewer — Test Before You Publish
Upload a thumbnail and title and see exactly how they look in YouTube search results, the home feed, the sidebar and on a phone — with the duration badge and title truncation.
In short
A YouTube thumbnail should be 1280 × 720 (16:9) under 2 MB and must stay readable at the 168-px sidebar size where most clicks happen — large face, three words maximum, high contrast, bottom-right corner clear for the duration badge; titles can be 100 characters but about 60 show on mobile.
Who this is for: YouTubers checking thumbnail legibility and title truncation before publishing.
What makes a thumbnail work
- Size: 1280 × 720 px (16:9), under 2 MB, JPG or PNG. Smaller images are upscaled and look soft; the wrong ratio gets black bars.
- Test at sidebar size: most clicks come from suggested videos where the thumbnail is 168 px wide. If the text or face is unreadable in that preview, simplify — three words maximum, large face, high contrast.
- Keep the bottom-right corner clear for the duration badge, and avoid thin text that disappears at small sizes.
- Title: up to 100 characters, but mobile shows about 60 before cutting off — front-load the keyword and the hook. Dark-mode viewers are the majority on mobile, so check both themes.
Nothing is uploaded; the preview is drawn locally from your image and text.
See also: TikTok & YouTube RPM Calculator.
Assumptions
- Previews are HTML mock-ups of YouTube search, home, sidebar and mobile cards at typical widths with 2-line title clamping.
- Checks: image ≥ 1280 × 720, 16:9 ratio, title ≤ ~60 characters for mobile.
- Nothing is uploaded; the image is shown from a local object URL.
Worked example
Preview shows the text fills a third of the frame and stays legible at 168 px; the 84-character title truncates after "How to calculate UAE gratuity in 2026 (step by…" on mobile — moving "2026" earlier keeps the key terms visible.
Frequently asked questions
What size should a YouTube thumbnail be?
1280 × 720 pixels, 16:9, under 2 MB, JPG/PNG/GIF.
How many characters of the title show on mobile?
Roughly 60 before truncation in most feeds; the full title appears on the watch page.
Can I preview Shorts thumbnails?
Shorts use a 9:16 vertical frame; this tool previews long-form 16:9 thumbnails. Use the crop tool for 9:16.
Is my thumbnail uploaded?
No — the preview is rendered in your browser.
How can I see how my thumbnail looks before uploading?
Upload the image and title here to preview the search, home, sidebar and mobile layouts in light and dark mode.
Why is my thumbnail blurry on YouTube?
It is below 1280 × 720 or not 16:9; YouTube upscales or crops it.
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