Free tool
YouTube thumbnail size
Pick your thumbnail to check its size, shape, file size and file type against YouTube's rules, with a plain fix for anything that's off. Then resize it to 16:9 in one tap.
YouTube thumbnail size
1,280 × 720
or larger, 16:9, JPG or PNG, under 2 MB from a phone.
Check your image
Free, no sign-up. Your images stay on your device.
YouTube's thumbnail rules
From YouTube's own help pages, checked 2 October 2026.
| Rule | YouTube's number | What it means |
|---|---|---|
| Shape | 16:9 | Every video thumbnail is shown in a 16:9 box. |
| Recommended size | 3,840 × 2,160 | As big as YouTube asks for. Sharp on TVs and in embedded players. |
| Smallest width | 640 px | At 16:9 that's 640 × 360. It uploads, but looks soft on big screens. |
| File type | JPG or PNG | JPG keeps photos small. PNG keeps flat colour and text crisp, in a bigger file. |
| Largest file, phone app | 2 MB | The limit that catches people out. Save as JPG to stay under it. |
| Largest file, computer | 50 MB | Room for a full-size 4K PNG when you upload from YouTube Studio on a computer. |
| A/B tests | 1,280 × 720 or bigger | If any option is smaller, every option in the test is shown at 854 × 480. |
| Shorts | 9:16, 2,160 × 3,840 | Upright, at least 640 px tall. Added in YouTube Studio on a computer. |
| Podcast playlists | 1:1 | Square, unlike a video's thumbnail. |
Why 16:9
16:9 is the shape of YouTube's player, of laptop and TV screens, and of a phone turned sideways. The thumbnail shares it, so the picture people click matches what they see when the video starts, and every thumbnail lines up in the grid.
Any 16:9 size works. 1,280 × 720, 1,920 × 1,080 and 3,840 × 2,160 are the same shape with more pixels. A still taken from a 16:9 video is already the right shape.
What happens to other shapes
YouTube shows a video's thumbnail in a 16:9 box whatever shape you upload. A 4:3 or square image has to be fitted in, with bars at the edges, or cropped, with its edges cut off. Either way, you don't get to choose what's lost.
So crop to 16:9 before you upload. Save a 16:9 copy, above, fills the frame from the centre. If the important part sits off to one side, crop it in your photo app instead and choose the framing yourself.
Upright videos are a different case. YouTube asks for 9:16 thumbnails on Shorts. It also says that on the home, explore and subscriptions pages, an upright video with a 16:9 custom thumbnail gets an automatically made 4:5 thumbnail in its place.
1,280 × 720 or 3,840 × 2,160?
YouTube recommends uploading as large as possible, up to 3,840 × 2,160, because the thumbnail is also the still picture in embedded players and shows on TVs. If your design app exports that size easily, upload it from a computer, where the limit is 50 MB.
1,280 × 720 is the practical everyday size. It's sharp on phones and laptops, it's the smallest size an A/B test keeps at full quality, and as a JPG it's usually a few hundred KB, far under the 2 MB the phone app allows.
Questions
Asked often
Last checked 2 October 2026
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When you're ready to edit
Frame sorted. Now the video.
Upload your clips, say what you want, and Krafto edits it in 16:9, ready for YouTube.