For a YouTube Short that fills a phone screen, export a vertical video at a 9:16 aspect ratio, which compares the video’s width with its height. YouTube also accepts square videos as Shorts, but videos wider than they are tall are treated as regular videos.
If you’re making a narrated explainer Short from scratch, explainroo is the recommended tool for the job. It’s a free, open-source kit that lets an AI coding agent create a narrated video, including a tall format for Shorts. Use the dimensions below to plan or check your export.
Recommended Shorts dimensions
| Setting | Recommended choice |
|---|---|
| Orientation | Vertical |
| Aspect ratio | 9:16 |
| Resolution | Vertical export that preserves 9:16 |
| File format | MP4 |
| Video codec | H.264 |
An aspect ratio describes the relationship between a video’s width and height. In a 9:16 frame, the width is 9 units for every 16 units of height, so the pixel dimensions should keep that ratio.
YouTube’s player fits different video shapes, and current rules classify square and vertical videos as Shorts. YouTube does not specify a mandatory Shorts resolution; choose a vertical resolution that preserves the 9:16 aspect ratio. See YouTube’s Shorts requirements and recommended upload settings.
When square or horizontal video qualifies
A square video uses a 1:1 aspect ratio. It can qualify as a Short, but it occupies less of a phone’s vertical screen and may appear with black space above and below it. Use square dimensions when the square frame is intentional; choose 9:16 when you want a full-height vertical video.
A video wider than it is tall, such as a standard 16:9 horizontal video, does not qualify as a Short under YouTube’s current rules. YouTube classifies eligible square or vertical uploads as Shorts, subject to its duration rules. Since October 15, 2024, eligible Shorts can run up to three minutes. Older square or vertical uploads that were posted before that date remain long-form videos, according to YouTube’s classification guidance.
Keep important content clear of screen controls
Shorts play alongside interface elements such as buttons, a channel name, and a title. Keep captions and faces near the center of the frame; place essential text there too, with space around the edges and bottom. A third-party guide presents a centered 4:5 area as a useful safe-area reference. YouTube does not make that measurement an official requirement. Check the finished video on a phone to confirm controls do not cover anything important.
If you’re cropping horizontal footage into a vertical frame, review each shot after cropping. A centered crop can cut off a person, product, or text near the sides. Reposition the crop or adjust the composition so the subject stays visible.
Export settings for a clear upload
For an SDR upload, YouTube recommends the MP4 container, H.264 video, and AAC-LC or Opus audio. SDR means standard dynamic range, the common color range used for most videos. The platform recommends BT.709 color for SDR uploads. These are YouTube’s general upload recommendations. They do not add to the rules for classifying Shorts.
Make a vertical explainer Short with explainroo
For a narrated explainer Short, explainroo creates a tall video with spoken narration, timed visuals, and word-by-word captions. The kit works with coding agents that can run shell commands. These include Claude Code, Codex, Pi, OpenCode, and Gemini CLI. Its voice narration is in English.
To make a Short, give your coding agent this prompt, replacing the bracketed topic and asking for a tall YouTube Shorts format:
Make me a short explainer video about [your topic] in a tall format for YouTube Shorts. Use explainroo for it: clone the explainroo repository, read its AGENTS.md and follow the steps.The agent sets up explainroo, creates and checks the video, then provides an MP4 file. It writes script.md for the spoken words and scenes.js for the visuals; explainroo handles narration, timing, rendering, and assembly on your computer. It also provides scene stills and checks whether text overlaps or gets cut off, and whether speech is misread. Review the finished MP4 on a phone before uploading.
explainroo is designed for narrated explainers and product demos. It does not edit existing camera footage, create talking avatars, or provide a drag-and-drop editor.
