YouTube 480p at 2.5 Mbps and 360p at 1 Mbps: size of a 60-second draft

YouTube's upload settings page recommends 2.5 Mbps for 480p and 1 Mbps for 360p (SDR, 24 to 30 fps). Multiply by length: a 60-second video is about 18.75 MB at 480p and 7.5 MB at 360p, before audio. The sums are mine, from the page's rates. Sume's Timeline docs list width, height and fps for output but no bitrate field, so the rate comes from the render, not from you.

The size arithmetic

Megabytes = megabits per second x seconds / 8. The audio track adds a little on top: the page recommends 128 kbps for mono and 384 kbps for stereo AAC-LC, which is roughly 1 MB and 2.9 MB per 60 seconds.

Why a draft at 480p is useful

The video generation docs show Seedance 2.5 offering 480p, 720p and 1080p, so a 480p model clip is a cheap look at motion and framing. The tier is a generation setting. It tells you nothing about the encoded file size of the final Timeline MP4, which depends on the render's encoder.

A Timeline render with output.width and output.height set to a 480p-class size is allowed, since the limits are even edges from 256 to 2160. It bills $0.10 per output minute, rounded up, whatever size you pick.

What Sume does not do

Sume does not let you choose a bitrate, and the docs do not promise one. If you need YouTube's exact recommended rate, measure the downloaded file; the page's numbers are guidance, not a rule that rejects a file.

Sume does not upload to YouTube either. Add the file in YouTube Studio and follow the page's other settings, such as frame rate matching the recording.

The useful takeaway is scale. A 60-second 480p draft is under 20 MB at the recommended rate, so sharing drafts for review is cheap, while the 1080p row at 8 Mbps is 60 MB for the same minute. If a reviewer's connection is the limit, send the draft tier; when you publish, use the higher tier that YouTube lists for your final resolution.