Skip to content
Mocknex
Esc
  • Popular
Open Studio

YouTube Thumbnail Size Checker

Drop in an image to check it against YouTube’s thumbnail requirements — dimensions, 16:9 ratio, minimum width, file type and the 2 MB limit — and see it at the sizes viewers see. If something’s off, fix it in one click.

  • Free, no sign-up
  • Runs in your browser
  • No watermark

About the size checker

The fix crops or pads the image to 16:9, resizes it to 1280×720 and compresses it as a JPG until it’s under 2 MB, then shows you the new file before you download it. It’s the quickest way to solve “Thumbnail too large” or a thumbnail with black bars, and nothing is uploaded — the image is processed in your browser.

Who it’s for

Anyone who has seen “thumbnail too large”, or has an image in the wrong shape and needs a 1280×720 version fast.

What makes it different

  • Drop, choose or paste an image — results appear instantly.
  • One-click fix: crop to fill or fit with blurred sides (no black bars), resize to 1280×720 and compress under 2 MB.
  • Previews at feed sizes with the timestamp badge, so you can spot hidden text.
  • Nothing is uploaded; the image is processed in your browser.

How to check a YouTube thumbnail size

  1. 1Drop an image onto the checker or choose a file.
  2. 2Read the checks: dimensions, aspect ratio, file type and file size.
  3. 3Look at the previews at feed sizes, with the duration badge in the corner.
  4. 4If needed, choose crop or fit and click “Fix and download” for a 1280×720 JPG under 2 MB.
Open the tool

Features

  • Checks dimensions, 16:9 ratio, minimum width, type and size
  • Previews at home, search, sidebar and mobile sizes
  • Duration badge overlay to spot hidden text
  • One-click fix: crop or fit, resize, compress under 2 MB
  • Drop, choose or paste an image
  • Processed in your browser

Common use cases

Upload errors
Fix a thumbnail YouTube rejects for being too large.
Wrong ratio
Turn a 4:3 or square image into a 16:9 thumbnail without black bars.
Final check
Make sure a designer’s file meets the requirements before upload day.

Tips

  • Design at 1280×720 or larger 16:9 from the start to avoid cropping later.
  • JPG is usually much smaller than PNG for photo-based thumbnails.
  • Check the duration badge — it covers the bottom-right corner in every feed.
YouTube Thumbnail MakerBold text, your photo and arrows on a 1280×720 canvas.YouTube Thumbnail PreviewYour thumbnail and title in the home feed, search and mobile.YouTube Thumbnail A/B TesterCompare 2–3 thumbnails side by side and in a feed.Thumbnail Text Generator2–5 word hooks, previewed in thumbnail style.
All creator tools

Guides

YouTubeYouTube Thumbnail Size and Requirements (and What YouTube Covers Up)1280×720, 16:9, under 2 MB — plus the corners YouTube covers and how to design for the size people really see.Oct 3, 2026 · 7 min read

Size Checker FAQ

What are YouTube’s thumbnail requirements?

A 16:9 image, ideally 1280×720 pixels, at least 640 pixels wide, in JPG, PNG, GIF or BMP format. Keep it under 2 MB — the limit for uploads from a phone; desktop uploads accept larger files.

How do I make my thumbnail smaller than 2 MB?

Save it as a JPG at 1280×720. The fix button does this automatically and lowers the quality just enough to fit.

Is my image uploaded?

No. Checking and fixing both happen in your browser.