What size is a YouTube thumbnail?
YouTube's own help page now asks for 3840 by 2160 pixels (16:9) for video thumbnails and 2160 by 3840 (9:16) for Shorts, with a minimum width of 640 pixels. The 1280 by 720 figure you'll see in many guides, including some of the best-known design tools, was the old recommendation.
A 1280 by 720 image still uploads. It just looks softer on large screens and TVs, where more and more YouTube is watched.
YouTube thumbnail requirements
Source: YouTube Help, “Add video thumbnails”, checked October 1, 2026. Sizes for every other network are in the social media image size guide.
- Video thumbnail: 3840 by 2160 pixels, 16:9.
- Shorts thumbnail: 2160 by 3840 pixels, 9:16.
- Minimum width: 640 pixels.
- Format: JPG or PNG.
- File size: 2 MB when uploaded from the mobile app, 50 MB from a computer.
- Account: custom thumbnails need a verified YouTube account.
- Shorts: custom Shorts thumbnails are added in YouTube Studio on a computer.
How to make a thumbnail that gets clicked
- Design for small first. Most people see it at the size of a thumbnail on a phone. If it doesn't read at that size, it doesn't work.
- Three words at most. The title already carries the words; the thumbnail carries the feeling.
- One face or one object, big and close, with strong contrast against the background.
- Keep the bottom right clear, where YouTube shows the video length.
- Match the promise. A thumbnail that oversells gets the click and loses the viewer, and YouTube notices both.
Post the video everywhere it belongs
Disclosure: PersonaXpand is our product. It publishes to YouTube along with Instagram, TikTok, Facebook and four other networks, so the short cut of your video can go to YouTube Shorts, Reels and TikTok in one step, each with its own caption. When the comments come in on YouTube, it drafts replies in your own voice for you to approve.