Guide, updated May 10, 2026 · 6 min read

Make YouTube Shorts with AI from one prompt

One sentence in, a vertical 9:16 Short out. No cropping a landscape video. No retyping the title. The video lands on your channel as a private draft and you flip it public when you are ready.

To make a YouTube Short with AI from a prompt, use a Script to Video tool that writes the narrative, generates the scenes, narrates the script, and renders vertical 9:16 video natively. You type one prompt, the tool produces a 9:16 video up to 3 minutes long with word-level captions sized for a phone screen, and YouTube auto-detects it as a Short on upload because it is vertical and within the Shorts length cap. With Dayvid, the same flow also sends the finished Short to your channel as a private draft, so you skip the manual upload form.

Most AI video tools were built for 16:9 first. You generate a horizontal video, then crop it to vertical, then watch the focal point drift off the side of the frame and the captions land in the wrong spot for a phone. Shorts creators end up redoing the same work each video. The cleaner path is a tool that targets vertical 9:16 from the start, treats captions as phone-readable by default, and keeps the whole thing under the 3-minute Shorts cap. That is what this guide walks through, using the Script to Video flow in Dayvid.

Cropped horizontal AI video vs vertical-native

StepCropped horizontal AI toolDayvid (9:16 native)
Aspect ratioMade at 16:9, cropped down, focal point driftsComposed at 9:16 from the first scene
Caption placementSized for a desktop frame, then squeezedWord-level captions sized for a phone screen
Scene lengthLong beats meant for landscape pacingShort beats that fit the 3-minute Shorts cap
Detected as a Short by YouTubeOnly if you remember to crop and trimVertical and within the Shorts length cap, detected automatically
Output to uploadRe-export, save, drag to YouTube StudioSent to your channel as a private draft
Batching a week of ShortsRe-crop and re-upload one by oneGenerate a batch, review as drafts, flip public on schedule

1Pick the Script to Video flow and set up your project

From the Dayvid dashboard, open the Script to Video flow. Name the project (this is what you and your future self see in the library), pick a preset if you already have a visual style saved, and confirm the brand the Short belongs to. The brand is the container that holds your YouTube channel connection later, so pick the right one if you run more than one channel.

  • ·Presets are a one-time setup. Save one for your channel's look (color grade, font, animation) and reuse it on every Short.
  • ·The flow is vertical 9:16 by default. There is no aspect-ratio toggle to remember.

2Write the brief in one prompt

On the Brief step, type a single sentence describing the Short you want. "A 50-second story about a deep-sea diver who finds a sealed door at the bottom of the trench." Dayvid drafts the script, breaks it into scenes, and writes the prompts for each scene image. Read the script. Edit the lines that feel off. Cut a scene if it pushes the runtime past your target length. Move on.

  • ·Treat the AI script as a first draft, not a final cut. The first scene matters most for retention on Shorts, so rewrite the opening if it is generic.
  • ·Aim for the runtime under the 3-minute Shorts cap. Anything longer and YouTube treats it as a regular video instead.

3Review the AI scenes and narration

On the Asset step, Dayvid generates a vertical image for each scene from the brief. Skim the grid. Regenerate the ones that miss the mark. The image is composed at 9:16, so the subject sits where it should on a phone screen. Then on the Voice step, pick a narration voice from the catalog and generate the narration. Listen to it once. If the pacing fights the Shorts cap, shorten a scene or two and regenerate.

  • ·Voices come from a fixed catalog. Pick one and stick with it across Shorts so the channel sounds consistent.
  • ·Scene images are saved to your library and reused if you regenerate the narration.

4Set captions and pick the music

On the Subtitles step, Dayvid auto-transcribes the narration and renders word-level animated captions. Read the transcript. Fix any misheard word (proper names are the usual suspects). The captions are sized for a phone, not a desktop, so they stay readable when the viewer holds the phone up close. On the Music step, pick a track from the in-app royalty-free library. Music in Shorts is a retention lever, not background noise. Pick something with a strong first 2 seconds.

  • ·Word-level captions help retention because the viewer's eye locks on the next word as it animates in.
  • ·Music comes from the in-app library. Custom music upload is not part of this flow.

5Style, elements, outro, and export

On the Style step, apply your visual preset. On Elements, drop in any overlay you reuse on every Short (a channel logo in the corner, a recurring sticker). On Outro, pick a short outro card or skip it (very tight Shorts rarely have room for one). Hit Export. Dayvid renders the final 9:16 video. While it renders, line up the title, description, and tags for the Short.

  • ·Skipping the outro is fine on Shorts. On a tight Short, the outro often eats the last seconds of the runtime, which hurts the loop.
  • ·Keep the tag list lean. 3 to 5 tags that match the topic does more than a 30-tag dump.

6Send it to your channel as a private draft

On the Publish step, pick the brand and the connected YouTube channel. Confirm the title, description, and tags Dayvid pre-filled from the project. Mark whether the Short is made for kids. Click publish. The Short uploads to your channel as a private draft. Open YouTube Studio (or the YouTube app on your phone) and flip privacy to public when you want it to go live. Because the video is vertical and within the Shorts length cap, YouTube auto-detects it as a Short and slots it into the Shorts shelf on your channel.

  • ·Batching: generate 5 Shorts in one session, review them as drafts, then flip them public across the week from your phone.
  • ·If you ever want to confirm what Dayvid is allowed to do with your channel, check Google's third-party apps with account access page.

Frequently asked questions

Up to 3 minutes for vertical (9:16) videos uploaded after October 15, 2024, per YouTube's current Shorts policy. Past the cap, the same video shows up as a regular long-form video instead. Dayvid renders vertical 9:16 by default, so you only have to watch the runtime against the current Shorts cap.

Yes. Vertical 9:16 is the default and only output. Every scene is composed for a phone screen, captions are sized for a phone, and the final video is 9:16. There is no aspect-ratio toggle and no horizontal export.

No. The flow renders vertical 9:16 only, by design. If your channel needs long-form 16:9 horizontal videos, this is not the right workflow for that.

Yes. Dayvid renders word-level animated captions sized for a phone screen, not a desktop. Each word lands on screen in sync with the narration, which holds the viewer's eye on the caption track and helps retention. You can edit the transcript before render to fix any misheard word.

Yes, when the video is vertical (9:16) and within YouTube's current Shorts length cap. YouTube auto-detects this on upload and slots the video into the Shorts shelf on your channel. You do not need to add #shorts to the title, though many creators do for habit. The technical signal is the aspect ratio and length.

It is optional. YouTube auto-detects Shorts based on aspect ratio and length, not the hashtag. Some creators still include it in the description as a habit and for searchability, but it is not required for the video to live in the Shorts shelf.

Yes. The flow is the same per Short, and the Publish step uploads each one as a private draft on your channel. Batch generate 5 Shorts in a session, review them all as drafts in YouTube Studio, then flip them public on the day each one is supposed to go up.

Yes. Once Dayvid uploads to your channel, the Short shows up in YouTube Studio as a private draft. Edit title, description, hashtags, end screen, thumbnail, all from Studio as you would for any upload. When you are ready, flip privacy to public.

Free tier is 300 credits with no card required, enough to test the flow on a short project. Paid plans start at $32.50 per month billed yearly with more credits per month. See the pricing page for credit allowance per plan. Sending the Short to YouTube does not cost extra credits, only the AI work that produces the video does (script, scenes, narration, captions, render).

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Sources and methodology

Stats, figures, and external references cited in this guide were taken from the linked sources on the dates listed below. Information may be out of date by the time you read this.