YouTube thumbnail size

Almost every guide gives the YouTube thumbnail size as 1280 × 720 pixels with a 2 MB ceiling. YouTube’s own help page says something different, and has for a while: it recommends 3840 × 2160, and the 2 MB figure applies only when you upload from a phone.

Both facts matter for different reasons. The resolution changed because the thumbnail is also the preview frame in the embedded player, where it can fill a large screen. The file size changed because the desktop and mobile upload paths were given different ceilings, and only one of them is the famous number.

Everything quoted below was read from YouTube Help, Add custom thumbnails on YouTube, on September 7, 2026. Anything derived from those figures by arithmetic says so.

What YouTube publishes for thumbnail size

The file size ceiling is not one number:

• Mobile: 2 MB for video thumbnails, 10 MB for podcasts.
• Desktop: 50 MB for video, Shorts and podcast thumbnails.

So a 6 MB thumbnail uploads perfectly well from a computer and is refused by the phone app. If an upload fails on your phone and works on your laptop, that is the reason, and nothing is wrong with the image.

Why 1280 × 720 is not wrong, only small

YouTube states a minimum width of 640 pixels for a video thumbnail. 1280 × 720 is comfortably above it, is exactly 16:9, and will be accepted without complaint. It has been the received answer for a decade because it used to be the recommendation.

What changed is where the picture ends up. YouTube’s page says the thumbnail “will be used as the preview image in the embedded player” and that it “should be as large as possible”. On a 4K panel a 1280-pixel-wide image is being stretched threefold before anyone presses play. Uploading at 3840 × 2160 costs you nothing except file size, and YouTube’s own downscaling to the small grid sizes is better than your file being upscaled to the large one.

The shape is the part that cannot be recovered. 16:9 is the frame; a 4:3 or square image gets fitted into it, and no amount of resolution repairs a crop. YouTube at least names one frame and means it, which is more than can be said for the three shapes Facebook lists for a single Facebook cover photo size.

The vertical video trap

There is one note on YouTube’s page that no size guide seems to repeat, and it changes what a thumbnail is for:

Vertical videos carrying a 16:9 custom thumbnail have it replaced by an auto-generated 4:5 thumbnail on the home, explore and subscription pages. Your custom image still shows on the watch feed, in watch history, and on non-mobile platforms.

In plain terms: if the video is vertical but not a Short, the thumbnail you designed is not what most people browsing on a phone will see. That is a reason to design the video’s opening frame carefully, not just the thumbnail file.

YouTube publishes no safe area

There is no official rectangle. YouTube’s guidance covers resolution, format, size and ratio, plus a policy section on what a thumbnail may not depict. It says nothing about margins, and nothing about which corners get covered.

That absence is a choice and not an oversight, because YouTube publishes a safe area for the other image on the same page. The channel banner gets a stated rectangle for text and logos; the thumbnail gets nothing. If you are working on both, the banner’s figures — and the thing everyone gets wrong about them — are in YouTube banner size.

The duration badge does sit over the lower-right corner in most surfaces, and the progress bar of a partly watched video runs along the bottom edge. Those are observations of a layout, not a specification, and YouTube changes its layout without announcement. Treat them as a reason to keep the lower-right corner uncommitted rather than as coordinates you can align against — a confident overlay drawn from someone’s screenshot is worse than no overlay, because it invites you to place your face right on a line nobody promised to keep still.

Working from a picture you already have

Most of the time the file exists and only needs bringing into line. Three situations cover nearly all of it.

The proportions are wrong. Nothing you do afterwards recovers a crop, so settle the shape before anything else. Doing the crop in one place and the scaling in another puts the photo through two rounds of resampling, the second of them working on an already-softened copy; the image resizer composes both into one mapping and reads the original once.

You do not trust the numbers you have been given. What Explorer or Finder prints in a column is the stored width and height, and a phone held sideways records its pixels one way round while tagging them to display the other. Image dimensions separates the two answers, and the displayed one is what YouTube measures.

The file weighs too much for the route you are using. Shrinking the picture is the wrong lever, because pixels are what YouTube recommends and bytes are only what it caps. Compress image hunts for a quality setting that lands under a target you name while the dimensions hold still. For an ordinary photographic thumbnail, simply saving as JPEG instead of PNG is often the entire fix.

There is no picture yet. Then start at 16:9 rather than bending something else into it. The YouTube thumbnail maker writes the recommended 3840 × 2160, and the identical shape at half and at a third of it, over a photograph or a flat background with whatever headline you type. It also names which of the two ceilings above your finished file has crossed.

Podcast artwork is a square instead, and square image handles that single job without dragging the other two into it.

A checklist before you upload

1. Decide which of the three you are making: video (16:9), Short (9:16), or podcast playlist (1:1). They are different shapes, not different sizes.
2. Match the shape first. Resolution errors only soften; shape errors crop.
3. Export at 3840 × 2160 for a video if you can, and never below 640 pixels wide.
4. Check where you are uploading from. 2 MB is the phone’s limit, 50 MB the computer’s.
5. Look at it at thumbnail scale before you commit. An image that reads at 3840 pixels wide can be unreadable in a sidebar, and the sidebar is where it competes.

Sources

• YouTube Help, Add custom thumbnails on YouTube — “Have a resolution of 3840 x 2160 pixels for videos and 2160 x 3840 for Shorts, with a minimum width of 640 pixels for videos and a minimum height of 640 pixels for Shorts”, “Be uploaded in image formats such as JPG or PNG”, “Mobile: 2 MB for video thumbnails or 10 MB for podcasts. Desktop: 50MB for video, Shorts, and podcast thumbnails”, and the note that “Vertical videos with 16:9 custom thumbnails will be replaced by an auto-generated 4:5 thumbnail on the home, explore, and subscription pages”. Read September 7, 2026.