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PlaylistTime / Creator tools / Thumbnail size checker

YouTube thumbnail size checker: check your image and fix it in one step

Pick your thumbnail image to check its size, shape, file type and file size against YouTube's rules. If something is off, get a fixed copy made in your browser.

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No file at hand? Type the numbers to check them.

This YouTube thumbnail size checker reads your image in the browser and checks it against the rules on YouTube's own help page: a 16:9 shape, at least 640 pixels wide, a JPG or PNG file, under 2 MB when you upload from a phone (50 MB from a computer), and 3840 x 2160 as the recommended size. Each rule gets a tick or a cross. If anything fails, the tool makes a fixed copy at once: it crops or fits the image to 16:9, resizes it and compresses it as a JPG under the limit you pick, and shows the file size before and after. It works as a YouTube thumbnail resizer and compressor, and nothing is uploaded.

What is the right YouTube thumbnail size?

YouTube Help (checked 26 October 2026) recommends a thumbnail of 3840 x 2160 pixels for videos, with a minimum width of 640 pixels, in a 16:9 shape. Any 16:9 size in between works: 1280 x 720 and 1920 x 1080 are both fine. Many guides still quote 1280 x 720 as the size to use; it passes every rule, but YouTube now asks for images "as large as possible", because the thumbnail is also the preview image in the player and is shown on large screens.

3840 x 2160: recommended1920 x 10801280 x 720640 x 360: minimum width

Every box is 16:9. Any size from 640 pixels wide up to 3840 x 2160 passes; larger keeps more detail on big screens.

YouTube thumbnail rules at a glance

RuleValueWhere it comes from
Recommended size3840 x 2160 (videos), 2160 x 3840 (Shorts)YouTube Help
Minimum640 px wide (videos), 640 px tall (Shorts)YouTube Help
Shape16:9 for videos, 9:16 for ShortsYouTube Help
File typeJPG or PNGYouTube Help, YouTube Data API
File size, phone2 MBYouTube Help
File size, computer50 MBYouTube Help, YouTube Data API

Older guides list a 2 MB limit for every upload and GIF and BMP as allowed types. The current help page names only JPG and PNG, and the API accepts only those two, so this checker treats any other type as one to convert.

How does the checker work?

Your browser opens the image file locally and reads three facts: the file type, the width and height in pixels, and the file size in bytes. Each is compared with the rules above. For the fix, the image is drawn on a canvas at the output size (your own width, kept between 640 and 3840, with the height set to 9/16 of it), then saved as a JPG. The tool tries quality 95 first and, if the file is over the limit, searches for the highest quality that fits. We count a megabyte as 1,000,000 bytes, the stricter reading of YouTube's "2 MB".

Worked example from our test on 26 October 2026: a 3000 x 2000 PNG test image (a photo-like picture we generated) of 2,037,082 bytes (2.04 MB). The checker marked two problems: the shape is 3:2, not 16:9, and the file is over 2 MB. With the default settings it cropped the image to 3000 x 1688 and saved a JPG of 753 KB at quality 95, under the 2 MB limit and ready for the YouTube app.

How to check and resize a YouTube thumbnail

Step 1: Pick your image

Choose the thumbnail file or drop it on the box. It is read in your browser and never uploaded.

Step 2: Read the checks

Each rule gets a tick or a cross: file type, width, 16:9 shape, file size and the recommended size.

Step 3: Adjust the fix if you like

Under More options pick the output size, how to reach 16:9 (crop, blurred background or black bars), the crop position and the file size limit.

Step 4: Save the fixed JPG

Compare before and after, then save the copy and upload it in YouTube Studio or the YouTube app.

How to make a thumbnail 16:9

How to make a YouTube thumbnail under 2 MB

Leave the file size limit at 2 MB and pick the image: the fixed copy is a JPG at the highest quality that stays under 2,000,000 bytes. A PNG screenshot is often several megabytes; the same picture as a JPG is usually a fraction of that with no visible change. If the copy still does not fit, choose a smaller output size such as 1920 x 1080 under More options. The 2 MB limit matters when you upload from the YouTube app on a phone; from YouTube Studio on a computer the limit is 50 MB.

Why does YouTube say my thumbnail is too big?

Most often the file is over 2 MB and you are uploading from a phone, or the file type is not JPG or PNG (a HEIC photo from an iPhone, for example). Run it through the checker, save the fixed JPG and upload that. If YouTube instead says you cannot add a custom thumbnail at all, the size is not the problem: YouTube Help says custom thumbnails need a verified account, and there is a daily limit on how many a channel can upload.

What size is a YouTube Shorts thumbnail?

For Shorts, YouTube Help recommends 2160 x 3840 in a 9:16 shape, at least 640 pixels tall, uploaded in YouTube Studio on a computer. This checker is for the 16:9 video thumbnail. For a Short, see the Shorts thumbnail grabber and the Shorts safe zone. YouTube Help also notes that a vertical video with a 16:9 custom thumbnail gets an automatic 4:5 thumbnail on the home, explore and subscription pages.

Thumbnail size vs how it looks in the feed

Passing the size rules does not mean the thumbnail reads well. On a phone the image is shown a few hundred pixels wide, and in the suggested list on a computer it is smaller still. Check that the text is big and the face or subject is clear with the thumbnail preview tool, which shows your image and title in a home feed, search results, the suggested list and a phone layout.

How accurate is this checker?

The pixel size, file type and file size are read from your file, so they are exact. The rules are YouTube's as published on 26 October 2026; YouTube can change them, and some limits (the daily number of thumbnails, for instance) depend on your channel and are not public. The file type comes from your browser, which reads it from the file name and contents; a renamed file can be misreported. The fixed copy is a standard JPG; colour profiles are converted to sRGB by the browser, which can shift some colours slightly.

Sources

Why we built this thumbnail size checker

Most pages about thumbnail size repeat 1280 x 720 and 2 MB, numbers YouTube's help no longer gives, and the resizers that exist ask you to upload your image to their server. Nitin Raja, who builds PlaylistTime, tested a lot of these pages before building this one: after testing out a lot of websites, he found what people need and what they do not, and built around that. People need today's rules with the source, a clear tick or cross for their own file, and a fixed copy without sending the image anywhere.

What this tool checks

Why it is different

This checkerA typical thumbnail resizer
Rules usedYouTube Help as of 26 Oct 2026, linkedOften 1280 x 720 and 2 MB from older guides
Your imageStays in your browserUploaded to a server
ResultA tick or cross per rule, then a fixed copyA resized file only
Under 2 MBHighest JPG quality that fitsA fixed quality setting
Not 16:9Crop, blurred background or black barsStretch or crop

Built by Nitin Raja. Last updated 26 October 2026.

Questions

What size should a YouTube thumbnail be?

YouTube Help recommends 3840 x 2160 pixels in 16:9, at least 640 pixels wide, as a JPG or PNG. 1920 x 1080 and 1280 x 720 also pass.

What is the maximum file size for a YouTube thumbnail?

2 MB when you upload from the YouTube app on a phone, and 50 MB from YouTube Studio on a computer, according to YouTube Help.

Is 1280 x 720 still the right thumbnail size?

It still passes every rule, but YouTube now recommends 3840 x 2160 and asks for thumbnails as large as possible.

How do I make my thumbnail smaller than 2 MB?

Pick it in the checker with the limit set to 2 MB. It saves a JPG at the highest quality that stays under 2,000,000 bytes.

What happens if my thumbnail is not 16:9?

YouTube resizes it without cropping and may add black bars. The checker can crop it, fit it on a blurred background or add the bars itself so you control the result.

Is my image uploaded anywhere?

No. The image is read and resized in your browser, and nothing is sent to PlaylistTime or anyone else.

All of them in one place: YouTube creator tools.