YouTube's resolution ladder: which rows Sume Timeline can render

YouTube's resolution help page lists eight recommended 16:9 sizes. Sume Timeline accepts even width and height from 256 to 2160 per edge, so 1920 x 1080, 1280 x 720, 854 x 480 and 640 x 360 are renderable, while 7680 x 4320, 3840 x 2160, 2560 x 1440 and 426 x 240 are not.

The sizes are from YouTube's page (read 2026-10-10); the Timeline limits are from its docs page. The comparison row by row is my arithmetic.

YouTube's list

The page says the standard aspect ratio for YouTube on a computer is 16:9 and lists these recommended resolutions: 4320p at 7680 x 4320, 2160p at 3840 x 2160, 1440p at 2560 x 1440, 1080p at 1920 x 1080, 720p at 1280 x 720, 480p at 854 x 480, 360p at 640 x 360 and 240p at 426 x 240.

What the rule means for a vertical file

The 2160 cap applies per edge, so a vertical 2160 x 3840 file is also out. A 1080 x 1920 vertical is in, and it is also the default. A 1440 x 2560 vertical is out for the same reason as the 2560 x 1440 row. If your plan needs 4K on YouTube, Timeline will not produce it. Use a different path for that, and keep Timeline for 1080p and below.

Timeline's width and height must be even integers. All the in-range rows above are even, so they pass that check.

Padding and black bars

The page also says YouTube's player adapts to each video's size, and that for cases such as 9:16 vertical videos on computer browsers YouTube may add more padding for optimal viewing, white normally or dark gray in Dark theme. It says to avoid adding padding or black bars directly to your video, because that interferes with the player adjusting to the viewer's device.

In Timeline terms that argues against the contain fit mode, which letterboxes. Use cover to fill the frame, or blur if you prefer a blurred fill, and accept that YouTube may pad vertical files on desktop.

• Cover: fills the frame, crops overflow.
• Contain: letterboxes, which the page advises against baking in.
• Blur: fills bars with a blurred copy.

Choosing a row

For a landscape YouTube video made in Sume, 1920 x 1080 is the practical top. Render at that size, keep the audio length within Timeline's 1 to 1800 seconds, and check duration and plan cost first with the plan call. If you need more than 30 minutes, render in parts. Cost is $0.10 per output minute rounded up per the docs.

If you do need a 4K deliverable, say so plainly in your plan instead of promising it from Timeline. The existing guidance in this blog covers the 2160-per-edge limit in more detail, and the point is the same: choose the tool that can produce the size you promise. For 1080p and below, Timeline renders cleanly, and YouTube's player will adapt to the file.

One last arithmetic note: 854 x 480 is 16:9 only approximately, since 854 divided by 480 is 1.779 rather than 1.778. YouTube lists it that way, and an even-edge render at exactly that size is accepted by Timeline. You do not need to match the ratio to the pixel for a 480p preview; just keep your fit mode on cover so no bars appear.