Free Thumbnail Size Checker
This thumbnail size checker lets you upload an image and instantly check its width, height, aspect ratio and whether it matches common thumbnail sizes.
It is useful for YouTube thumbnails, blog images, website cards, social posts, product images and checking whether an image is the right shape before uploading it and swearing quietly.
How To Use This Thumbnail Size Checker
Choose an image from your device. The tool will show the image dimensions, aspect ratio and a quick comparison with common thumbnail formats.
Common Thumbnail Sizes
YouTube thumbnails commonly use 1280 x 720 pixels with a 16:9 ratio. Square thumbnails often use 1080 x 1080 pixels. Vertical thumbnails and short-form covers commonly use 1080 x 1920 pixels.
Image Privacy Note
This tool checks the image in your browser. The image is not uploaded or stored by BestBlog.
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Thumbnail Size Checker FAQ
Does this check YouTube thumbnail size?
Yes. It compares your image with the common 1280 x 720 YouTube thumbnail size and 16:9 ratio.
Can it check square thumbnails?
Yes. The tool also identifies square images, which are commonly used for profile images, cards and social posts.
Does this upload my image?
No. The image is checked in your browser and is not uploaded to BestBlog.