# YouTube thumbnail size checker: resize to 1280 × 720 or 3840 × 2160

> Check a thumbnail against YouTube's rules: 16:9, at least 640 pixels wide, 3840 × 2160 recommended, 2 MB from the app and 50 MB from a computer. Crop it to 4K, 1080p or 720p.

URL: https://cutfac.com/tools/youtube-thumbnail-size  
Last updated: 2026-10-28  
Language: [한국어](https://cutfac.com/ko/tools/youtube-thumbnail-size)

Drop in a thumbnail to check its shape, resolution and file size against YouTube's rules, then crop it to the size you need. The image stays in your browser.

Runs in your browser. Nothing is uploaded.

## How to use it

1. **Add a thumbnail.** Drop a JPG or PNG. It isn't uploaded.
2. **Read the check.** Shape, resolution and file size are checked against YouTube's rules, and the preview shows it in a 16:9 frame as YouTube does.
3. **Crop to size.** Pick 3840 × 2160, 1920 × 1080 or 1280 × 720. The middle of the image is cut to 16:9 and saved as a JPG, with its file size shown.

## YouTube's thumbnail rules

YouTube asks for a 16:9 image, as large as possible: it recommends 3840 × 2160 pixels and needs at least 640 pixels wide. JPG and PNG both work. A thumbnail uploaded from a computer can be up to 50 MB; from the YouTube app, 2 MB. Custom thumbnails need a verified account.

## 1280 × 720 or 3840 × 2160

Most guides still say 1280 × 720. YouTube accepts it, since it's well over 640 pixels wide, but its current recommendation is 3840 × 2160, which stays sharp on large monitors and TVs.

- 3840 × 2160: sharpest. As a JPG it can pass 2 MB, so upload it from a computer.
- 1920 × 1080: sharp on most screens and smaller.
- 1280 × 720: the smallest common size, for the 2 MB limit in the app or a small source image.
- The tool shows each download's file size, so you can see whether it fits under 2 MB.

## Before you upload

A thumbnail is seen small: in the sidebar it's about 168 pixels wide. Once the size is right, check that its text still reads at that size with the YouTube thumbnail tester, which previews it next to other videos.

## Sources

- [YouTube Help: Add custom thumbnails on YouTube](https://support.google.com/youtube/answer/72431)

## Questions

### What size should a YouTube thumbnail be?

16:9 and as large as you have: YouTube recommends 3840 × 2160 and needs at least 640 pixels wide. 1920 × 1080 and 1280 × 720 work too.

### Is 1280 × 720 still okay?

Yes. It's above the 640-pixel minimum, so YouTube takes it. It's just softer than 3840 × 2160 on large screens.

### Why can't I upload my thumbnail from my phone?

The YouTube app takes thumbnails up to 2 MB. Download a smaller size here, or upload it from a computer, where the limit is 50 MB.

### What about Shorts thumbnails?

Shorts thumbnails are vertical, 9:16, and are added from YouTube Studio on a computer. This tool is for regular, horizontal videos.

### Is my image uploaded?

No. It's checked and cropped in your browser. Nothing is sent anywhere.