YouTube Thumbnail Size Checker
Check your thumbnail against YouTube's requirements — resolution, 16:9 ratio, 2 MB limit and format — and see how it reads at the small sizes viewers actually see.
- Runs in your browser
- Instant
- Free
Drop your thumbnail here or click to choose
JPG, PNG, GIF or WebP. The image stays on your device.
How it looks at small sizes
Most viewers see your thumbnail at these widths. If the face or text is hard to read here, simplify it.
YouTube's thumbnail requirements
According to YouTube Help, a custom thumbnail should:
- have a resolution of 1280 × 720 pixels, with a minimum width of 640 pixels;
- be a JPG, GIF or PNG file;
- stay under the 2 MB limit;
- use a 16:9 aspect ratio, the same as the YouTube player.
Custom thumbnails also need a verified YouTube account. Requirements can change, so check the help page if an upload is refused.
What the small-size previews tell you
A thumbnail is designed at 1280 × 720 but usually seen at a fraction of that — a few centimetres wide on a phone. The previews above draw your image at typical feed, search and sidebar widths and add a duration badge in the bottom-right corner, where YouTube places the video length. Text that sits in that corner gets covered, and small text that looks fine on your monitor often turns into a blur at 168 pixels wide.
- Keep the main subject large and close to the centre or left third.
- Use three to five words of text at most, in a heavy font with strong contrast.
- Leave the bottom-right corner free of anything important.
How to fix a failed check
- Not 16:9: crop with the 16:9 preset in the image cropper, or let the thumbnail enhancer produce 1280 × 720.
- Too small: upscale with the thumbnail enhancer — and if possible start from a larger frame or photo.
- Over 2 MB: use compress to 2 MB; JPG at good quality is usually far below the limit.
- WebP or HEIC: convert with WebP to JPG or HEIC to JPG.
More detail: YouTube thumbnail size, resolution and quality guide · making thumbnail text readable on mobile.
Frequently Asked Questions
What size should a YouTube thumbnail be?
YouTube Help recommends 1280 × 720 pixels with a minimum width of 640 pixels, a 16:9 aspect ratio, JPG, GIF or PNG format, and a file under 2 MB.
Is my thumbnail uploaded when I check it?
No. The checker reads the file in your browser; the image is not sent to a server.
Why does the preview show black bars?
Your image is not 16:9. The preview fits it inside a 16:9 frame the way a player does. Crop it to 16:9 or use the thumbnail enhancer to get a clean 1280 × 720 image.
Why is there a 12:34 box in the corner?
It stands in for the video length that YouTube shows in the bottom-right corner of thumbnails, so you can see whether it covers anything important.