What is the best size for a YouTube thumbnail?

3840 × 2160 pixels, in a 16:9 ratio. That's the resolution YouTube's Help Center recommends for video thumbnails in 2026. The minimum width is 640 pixels, and the file must be a JPG or PNG under 2 MB if you upload from a phone, or under 50 MB from a computer.

Is 1280 × 720 still a good YouTube thumbnail size?

It still works: it's 16:9 and wider than the 640-pixel minimum, so YouTube accepts it. But it's no longer what YouTube recommends. Designing at 3840 × 2160 keeps your thumbnail sharp on large screens and TVs, and you can always export a lighter version if the file gets too big.

Why can't I upload a custom thumbnail on YouTube?

The most common reason is that your account isn't verified: YouTube only lets verified accounts upload their own thumbnails. Other causes are an unsupported format (use JPG or PNG), a file above the size limit (2 MB on mobile) or, for Shorts, trying from the app instead of YouTube Studio on a computer.

What size is a YouTube Shorts thumbnail?

2160 × 3840 pixels, a vertical 9:16 image. According to YouTube, custom Shorts thumbnails can currently only be added in YouTube Studio on a computer, and your account must be verified. Keep the main subject in the centre, since Shorts previews are often cropped in feeds.

YouTube Thumbnail Size 2026: Official Specs & Tips

The official YouTube thumbnail size in 2026 is 3840 × 2160 pixels (16:9), according to YouTube's own Help Center, with a minimum width of 640 pixels, JPG or PNG format, and a maximum file size of 2 MB from a phone or 50 MB from a computer. For Shorts, the recommended size is 2160 × 3840 pixels (9:16).

Many guides still quote 1280 × 720. That size remains valid, but it's no longer what YouTube recommends. Below you'll find the current official specs for videos and Shorts, how to add and test a custom thumbnail, and design tips for thumbnails that get clicked.

YouTube thumbnail size and requirements

Requirement	Videos	Shorts
Recommended size	3840 × 2160 px	2160 × 3840 px
Aspect ratio	16:9	9:16
Minimum width	640 px	640 px
File formats	JPG or PNG	JPG or PNG
Max file size (mobile)	2 MB	Set in YouTube Studio on a computer
Max file size (computer)	50 MB	50 MB
Eligibility	Verified account	Verified account

Source: YouTube Help, Add video thumbnails.

3840 × 2160 or 1280 × 720?

Both are 16:9, and both are accepted. The difference is sharpness: a 3840 × 2160 thumbnail stays crisp on large monitors and smart TVs, where a 1280 × 720 image can look soft.

In practice:

Design at 3840 × 2160 in your editor (Canva, Figma, Photoshop or similar).
Export as JPG for photos, or PNG for flat graphics and text.
Check the file size. If you upload from the YouTube app, stay under 2 MB; from a computer, you have up to 50 MB.

If your tool can't handle 4K, 1920 × 1080 or 1280 × 720 are fine fallbacks: the ratio is what matters most, since a wrong ratio leads to black bars or cropping.

YouTube Shorts thumbnail size

Shorts use a vertical 2160 × 3840 pixel (9:16) thumbnail. Two limitations to know:

Custom Shorts thumbnails can currently only be added in YouTube Studio on a computer.
Your account must be verified, as for regular videos.

Without a custom image, you can still pick one of the thumbnails YouTube suggests automatically.

How to add a custom thumbnail

Verify your account if you haven't already (YouTube asks for a phone number).
Open YouTube Studio, then Content, and select your video.
In Details, under Thumbnail, choose Upload file.
Select your JPG or PNG and save.

If the upload fails, the cause is almost always the account verification, the file format or the file size.

Tips for thumbnails that get clicked

Specs get your thumbnail accepted; design gets it clicked.

Design for a small screen. Most people see your thumbnail at the size of a thumb on a phone. Zoom out: if you can't read it at 20%, simplify.
Use a few big words. Three to five words are plenty, and they should add to your title rather than repeat it.
Show a clear subject. A face, a product or a before/after reads faster than a busy scene.
Mind the bottom-right corner. YouTube displays the video duration there, so don't place text or logos in that spot.
Stay consistent. Similar colours, fonts and layouts help subscribers spot your videos in their feed.
Keep your promise. A thumbnail that doesn't match the video may earn a click, but viewers leave fast, and that hurts the video.

A/B test your thumbnails with Test & compare

YouTube Studio's Test & compare feature lets you test up to three thumbnails on the same video. YouTube shows the versions to different viewers and picks a winner based on watch time share. Results can take from a few days up to two weeks, and the feature is available in YouTube Studio on a computer (YouTube Help).

Test clearly different ideas (a face versus a product shot, for example) rather than small colour changes, since bigger differences reach a result faster.

Schedule YouTube videos with their thumbnail

When you schedule a YouTube video in Wavnil, you can attach your custom thumbnail along with the title, description and tags, and it's set when the video is published. YouTube's API accepts JPG or PNG files up to 50 MB (YouTube Data API); your account still needs to be verified for the thumbnail to be applied.

Planning Shorts too? Check how long YouTube Shorts, Reels and TikToks can be, and find a name for a new channel with our free YouTube name generator.

Quick recap

Design your thumbnails at 3840 × 2160 (16:9), export JPG or PNG, and stay under 2 MB if you upload from your phone. Use 2160 × 3840 for Shorts, verify your account, and test your best ideas with Test & compare. To publish your videos on schedule, try Wavnil free for 7 days.

Sources

YouTube Help, Add video thumbnails.
YouTube Help, Test & compare thumbnails.
Google for Developers, YouTube Data API: Thumbnails: set.