As of September 2026, YouTube's Add custom thumbnails page says a video thumbnail should have a resolution of 3840 by 2160 pixels, an aspect ratio of 16:9, and an image format such as JPG or PNG. That is newer than the 1280 by 720 most guides still repeat.
The hard limits inside it are a minimum width of 640 pixels and a file size cap that depends on where you upload from: the same page says 2 MB from the mobile app and 50 MB from desktop. A smaller 16:9 image still uploads, 1280 by 720 included; it is just no longer the size YouTube names.
For Shorts the shape turns on its side: 9:16, portrait. The same page names 2160 by 3840 pixels with a minimum height of 640; 1080 by 1920 is the size most people work at. You cannot get one by cropping a landscape thumbnail, and we go through the arithmetic below.
The numbers are the easy part. What decides whether a thumbnail works is how it survives being shrunk to a couple of hundred pixels wide on a phone, and which corners YouTube covers with its own badges. Here is the full reference.
What size is a YouTube thumbnail?
The thumbnail size for YouTube, in one line: 3840 by 2160 pixels, 16:9, JPG or PNG, up to 50 MB from desktop. As of September 2026, YouTube's Add custom thumbnails page says exactly that; if you only remember one line, that is the line. If the line you remember is 1280 by 720, that still uploads.
YouTube thumbnail size at a glance
- A video, 16:9. 3840 by 2160 recommended, at least 640 pixels wide, JPG or PNG, up to 2 MB from the YouTube app on a phone or 50 MB from a computer. Set in YouTube Studio on a computer or in the YouTube app.
- A Short, 9:16. 2160 by 3840 recommended, at least 640 pixels tall, JPG or PNG, up to 50 MB. Set only in YouTube Studio on a computer.
- A podcast playlist, 1:1. A square image, JPG or PNG, up to 10 MB from the YouTube app on a phone or 50 MB from a computer. The page names no pixel size for it.
The YouTube thumbnail dimensions in that line answer three questions at once. 3840 by 2160 is the resolution, the count of pixels across and down. 16:9 is the aspect ratio, the shape: the relationship between those two numbers, not the numbers themselves. JPG or PNG is the format. File size is a separate cap, set by upload route: the same page says 2 MB from mobile and 50 MB from desktop.
The three are independent: a 1920 by 1080 image is a different resolution but the same shape, and a 3840 by 2880 image has the right width and the wrong shape. Most bad uploads come from getting one right and assuming the other two follow.
YouTube thumbnail sizes and requirements, in full
What YouTube asks of the image itself, in one place, as its Add custom thumbnails page reads in September 2026. The YouTube thumbnail sizes differ by upload: one for a video, one for a Short, and a square for a podcast playlist.
- Resolution: 3840 by 2160 for videos, 2160 by 3840 for Shorts. The page's own wording is to "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." So 3840 by 2160 is the recommendation and 640 wide is the floor. Anything in between is accepted.
- Aspect ratio: 16:9 for videos, 9:16 for Shorts. The shape of the video player and of nearly every place a thumbnail appears. The same page words it as a recommendation ("try to upload a thumbnail with an aspect ratio of 16:9", and 9:16 for Shorts), but anything else is padded or cropped to fit.
- File size: 2 MB from the mobile app, 50 MB from desktop. The same page gives two limits: "Mobile: 2 MB for video thumbnails or 10 MB for podcasts" and "Desktop: 50MB for video, Shorts, and podcast thumbnails." So the 2 MB most guides quote is the app limit; from a desktop browser you have 50 MB. A JPG lands well under both; a large PNG of a photograph is the usual way over the mobile one.
- Formats: JPG or PNG. The page's wording is "image formats such as JPG or PNG", and those are the only two it names. JPG for anything photographic; PNG for flat graphics with hard edges. Older guides add a third because the page used to: an archived copy from December 2023 read "JPG, GIF, or PNG", beside a 1280x720 resolution and a 2MB cap, which is where both of those old numbers come from. GIF is no longer on the list, and a thumbnail was always one still image.
- Podcast playlists: 1:1. The same page asks for a square thumbnail on a podcast playlist, and allows it 10 MB from the mobile app and 50 MB from desktop. The YouTube playlist thumbnail post covers how to add one and what it should say.
- Smaller is accepted. The 4K figure is the recommendation, not the floor. Any 16:9 image at least 640 pixels wide uploads, so 1280 by 720, 1920 by 1080 and 2560 by 1440 all still work; YouTube scales whatever you send into the sizes it serves.
Two more things apply outside the image. The same page says "your account must be verified to use this feature"; YouTube's Verify your YouTube account page, read the same month, says verification is a phone number and a code by text or voice call, and lists custom thumbnails among what it unlocks. If the option is missing in Studio, start there, then read why a custom thumbnail will not upload. The picture also has to pass the same rules as the video: YouTube's Thumbnails policy page, read the same month, says thumbnails that violate its Community Guidelines are not allowed.
Resolution versus size: two words, two limits
The two words get used for each other, and YouTube's page sets a separate limit on each. Resolution is the pixel count of the image, width by height: 3840 by 2160 is the resolution YouTube names for a video thumbnail, and 640 pixels wide is the least it accepts. Size, on the same page, is the file's weight in megabytes: 2 MB from the mobile app, 50 MB from desktop. A thumbnail can pass one and fail the other.
A 4K PNG of a photograph is the right resolution and, from the app, the wrong size; a 500 pixel wide JPG is a tiny file at a resolution the upload refuses.
If you searched for YT thumbnail resolution, the number is 3840 by 2160 for a video and 2160 by 3840 for a Short, and the reason it is that large is where thumbnails are now shown. As of September 2026, YouTube's Add custom thumbnails page words it as a recommendation to "have a resolution of 3840 x 2160 pixels", not a requirement; the same page keeps the 640 pixel floor.
Between the two, YouTube makes the smaller versions it serves in feeds itself, so a 1920 by 1080 or a 1280 by 720 source is scaled rather than rejected. What a larger source buys you is a cleaner result on the biggest screens, a television above all, where a 1280 wide image has to be stretched to fill the tile.
The practical rule: export at the largest resolution your source honestly has, at an exact 16:9, and check the file weight before uploading from a phone. Never upscale a small image to hit 3840; it adds pixels, not detail, and the blur shows on a television.
If you want the numbers checked for you before you upload, the thumbnail size and quality checker reads the resolution, the ratio and the file weight of an image and says which of YouTube's limits it passes. If the frame is wrong, the YouTube thumbnail resizer can fit or fill it into 16:9 or 9:16 without stretching the image.
Why the shape matters more than the pixel count
Resolution is the least important of the three, because YouTube does not show the file you upload. It re-encodes it into several smaller versions and serves whichever one fits the slot, and the slots are small. (A soft thumbnail usually has another cause; why a YouTube thumbnail is blurry lists them in order.)
In a search result or a suggested-video list on a phone, a thumbnail can render at under 200 pixels wide. On a desktop it is a few hundred pixels across. Every one of those is a downscale, and a downscale only throws detail away.
So the question is not how many pixels you gave YouTube, but what is left when most are gone. Three words in a heavy typeface survive: WORTH IT? does. A sentence does not. A face filling a third of the frame survives; a face in a wide shot becomes a dot.
The shape matters more because it is the one thing never scaled away. A 16:9 image fills a 16:9 slot edge to edge at every size. An image at the wrong ratio is padded or cropped at every size, and the padding is the first thing a viewer notices.
Resolution is what you upload. Shape is what the viewer gets.
A quick test
Look at the finished thumbnail at about 200 pixels wide. If the words are still readable and the subject still says what the video content is, it will read in a feed. If you have to lean in, the feed will not lean in for you.
What about Shorts thumbnails?
A Shorts thumbnail is 9:16, the portrait shape of the Short itself: as of September 2026, YouTube's Add custom thumbnails page names 2160 by 3840 pixels with a minimum height of 640, uploaded only in YouTube Studio on a computer. The video's own size, its length, the safe zone and why a cropped landscape thumbnail fails are in YouTube Shorts size and dimensions, and the YouTube Shorts thumbnail maker designs one for the tall frame.
The parts of a thumbnail YouTube covers up
YouTube lays things on top of your thumbnail, none of them in the file you upload. Design without them in mind and the parts you cared about most end up covered.
- The duration badge, bottom right. A dark label with the video length sits bottom right in nearly every list and feed. A number, a logo or the last word of a line placed there is under it.
- The rounded corners. Thumbnails show with rounded corners across YouTube's current design, so anything pushed hard into a corner loses its tip. Keep borders and corner badges a little inboard.
- The watched bar, along the bottom. A red progress line runs along the bottom edge of any video a viewer has started. A thin strip of text along the bottom ends up underlined by it.
- Hover controls, top right. On the desktop site, watch-later and queue buttons appear top right when the cursor is over the thumbnail. Not permanent, but no place for anything essential.
- On Shorts, the lower part of the frame. In the Shorts shelf and on a channel's Shorts tab, the view count and title sit over or beneath the lower part of the image, depending on the device. Keep readable words in the upper two thirds.
The practical rule is a margin: keep the words and the face a little in from every edge, and treat the bottom-right corner of a 16:9 thumbnail and the bottom of a 9:16 one as YouTube's.
Where your YouTube thumbnail image is shown
One file does several jobs, and most of them are small. As of September 2026, YouTube's Impressions & click-through-rate FAQs page says your video thumbnails are always competing against other videos on the homepage, in Up Next on the watch page, in search results and in subscription feeds. In the YouTube app on a phone those are the smallest tiles of all. On your YouTube channel page the same thumbnail images sit in a grid beside your other uploads, so the viewer who arrives there compares them with each other.
Two places are outside YouTube. As of September 2026, the Add custom thumbnails page says the thumbnail is used as the preview image in the embedded player, which makes it the first thing a reader sees on any website that embeds the video.
And when someone shares the link on social media or in a chat app, the preview card usually shows the thumbnail too: a watch page we checked in September 2026 names the video's thumbnail as its share image in the page code, declared at 1280 by 720. That is one more place the design has to work at a size you did not choose, so check the image small before you upload, not only at full size in an editor.
Common mistakes with thumbnail dimensions
The ones we see most often.
- Uploading a square or a 4:3 image. Old camera exports and social crops are the usual sources. YouTube fits them into the 16:9 slot with bars at the sides, and the bars are the first thing anyone sees. A community post is the reverse case, where the feed shows the image square, as the YouTube community post image size post explains.
- Stretching to fit. Stretching a 4:3 image to 16:9 keeps the pixels and ruins the faces. If the source is the wrong shape, crop it or build it again.
- Trusting a template's canvas. Thumbnail templates in design tools open at whatever size their maker chose. Check that the canvas is exactly 16:9, or 9:16 for a Short, before the first element goes on it; a 1280 by 720 template still uploads, and the shape is what cannot be fixed later.
- Hitting the mobile file size limit with a PNG. As of September 2026, YouTube's Add custom thumbnails page caps an upload from the mobile app at 2 MB for video thumbnails, and a full-resolution PNG of a photograph can be several megabytes. Export a high-quality JPG instead, or upload from a desktop browser, where the same page allows 50 MB. The YouTube thumbnail compressor finds the highest JPEG quality that fits under 2 MB.
- Cropping a landscape thumbnail for a Short. Still the most common Shorts mistake: a 9:16 slice keeps about a third of a 16:9 frame, and the center third of a landscape design is usually the least interesting third.
- Reading the words only at full size. A thumbnail that reads at full export size and fails at 200 wide has failed. Check it small before you upload it.
- Letting the corners carry meaning. Numbers, logos and part-two badges in the bottom right sit under the duration label. Move them up or inward.
What WThumb gives you
Everything above is a list of things to check by hand. We decided the shape should never be one of them.
A finished thumbnail from WThumb is a Full HD+ JPEG, sharper than 1080p: 2048 by 1152 pixels at an exact 16:9 for YouTube, or 1152 by 2048 at an exact 9:16 for Shorts. Against YouTube's Add custom thumbnails page, read in September 2026, it sits above the 640 pixel minimum width and below the 3840 by 2160 recommendation; YouTube re-encodes every upload into smaller versions anyway, so the shape and what survives the shrink matter more than the count. Nothing to resize, no ratio to correct.
Paste a YouTube link (we fetch only that video's public thumbnail) or upload a reference image, type up to three lines of words, and tick 16:9, 9:16 or both. Add your photo and you are placed in the design; skip it and you get a faceless version, with the person in the reference removed and nobody else's face put in. Each shape is designed for its own frame, and one brief can give you one or two designs.
The reference is a brief, not a template. WThumb keeps the subject, the visual idea, the energy and the role each element plays, and designs the layout, the framing, the typography, the color treatment and the graphic structure itself. That is what makes a vertical version possible from a landscape reference: the idea carries over; the design is new for each shape.
A run takes about thirty seconds. Press the pencil on a finished thumbnail and describe one change in plain words, such as move the words higher, and WThumb makes a new version. Each revision costs one credit (1 credit = 1 thumbnail). There is no editor afterwards, no canvas and no layers, so put the safe areas in your instructions if they matter: keep the bottom right clear is a good one.
On WThumb, new accounts get two free credits, and no card is needed; the paid plans are on the pricing page. Your words go through a moderation check before anything is generated; a refused request is never generated and costs nothing.
