YouTube Thumbnail Size: The Ultimate Guide (2025)

Your thumbnail is the most critical metadata for your video. Even before reading the title, viewers process the image. If it's blurry or cropped incorrectly, you lose the click.

The Perfect Dimensions

According to Google's official guidelines, your custom thumbnail image should be as large as possible. The recommended resolution is 1280x720 pixels.

• Minimum width: 640 pixels.
• Aspect Ratio: 16:9 (standard for HD players).
• Max File Size: Under 2MB.
• Formats: JPG, GIF, BMP, or PNG.

Why 1280x720?

Although thumbnails appear small in the sidebar, they are often displayed full-width on high-resolution screens (like Smart TVs and Retina displays). A 1280px wide image ensures it looks crisp on any device.

Common Mistakes to Avoid

The most common error is using a 4:3 aspect ratio image, which results in black bars (letterboxing) on the sides. Always crop your image to 16:9 before uploading.