16:9 aspect ratio
16:9 is the widescreen shape: 16 units wide for every 9 tall, which is 1.7778 as a decimal. 3840 x 2160 px is 16:9 because 3840 divided by 2160 gives 1.7778, and the fraction reduces to 16:9. 6 of the image sizes on this site use it.
Where 16:9 comes from
16:9 came out of television. It was chosen as the international standard for high-definition broadcast and it carried over to computer displays, then to online video, and from there to every thumbnail and preview that sits in front of a video. It is why a YouTube thumbnail is this shape and not another.
Which platforms use 16:9
Read live from the specification data, so this list changes when a platform does. Last verified 2026-07-27.
| Platform | Asset | Size (px) | Source |
|---|---|---|---|
| YouTube | Thumbnail | 3840 x 2160 | Documented |
| YouTube | Channel banner | 2560 x 1440 | Documented |
| X (Twitter) | In-stream image | 1600 x 900 | Convention |
| Profile cover | 800 x 450 | Convention | |
| Discord | Server banner | 960 x 540 | Convention |
| Twitch | Offline banner (video player) | 1920 x 1080 | Convention |
16:9 in pixels
Every row below is calculated from the ratio rather than looked up, so the heights are exact where the arithmetic is exact and rounded to the nearest whole pixel where it is not. A fractional pixel is not something a file can store.
| Width | Height | Used by |
|---|---|---|
| 800 px | 450 px | Pinterest profile cover |
| 960 px | 540 px | Discord server banner |
| 1600 px | 900 px | X (Twitter) in-stream image |
| 1920 px | 1080 px | Twitch offline banner (video player) |
| 2560 px | 1440 px | YouTube channel banner |
| 3840 px | 2160 px | YouTube thumbnail |
Cropping and letterboxing into 16:9
Because it is the native shape of most displays and cameras, a 16:9 crop of a landscape photo usually loses very little. Going the other way, a portrait source in a 16:9 frame either loses most of its height or gets pillarboxed.
There are only two honest ways to put an image of one shape into a frame of another. Crop to fill keeps the frame full and throws away whatever does not fit, which is almost always what you want for a feed. Fit inside keeps the whole image and pads the remaining space, which is what you want when the image is a diagram, a screenshot or anything where losing an edge loses meaning. Scaling to fit without doing either, so the image is stretched, is the one option that is always wrong.
Work out a 16:9 size
Enter a width or a height and the calculator solves the other side. It runs in your browser and nothing is uploaded.
Other ratios
See the aspect ratio guide for the shapes side by side, or the full cheat sheet for every size on one page.