How do I make AI videos for TikTok?
Pick one recurring character, write the video as a short timed script, render it vertical (9:16) in an AI video tool, then post it with TikTok's AI-generated content setting switched on if it looks realistic[1]. Seedance 2.0, for example, caps a single clip at 15 seconds[4], so plan one or two beats per clip.
The workflow we use
- Fix the character. One reference picture and one written description (face, hair, outfit, voice, attitude) that you reuse in every video. A character people recognise is what turns separate clips into an account. How to keep an AI character consistent covers the techniques.
- Pick a format people already know. A livestream, a tutorial, a storytime, a dance trend. The format tells both the viewer and the model what happens next. Ideas with prompts are in What kinds of AI videos do well on TikTok?.
- Write the prompt as a timeline. Give each beat a time range, one action and an exact quoted line, plus where the camera is. Our Seedance prompting field guide has the skeleton, and the free video prompt builder assembles one for you.
- Render vertical and short. Ask for 9:16. Seedance 2.0 outputs 4 to 15 seconds per clip in ratios including 9:16[4], and Veo 3.1 also renders 9:16[5]. For a longer video, chain clips from the last frame of the previous one; see How to make AI videos longer.
- Label and post. Turn on the AI-generated content setting before posting when the video looks realistic; it is required for realistic content and encouraged for the rest[1]. Steps are in How do I label a video as AI-generated on TikTok?.
Which tools are free to start
Free tiers change often, so these are what each company's own page said when we checked. Free plans commonly add a watermark.
| Tool | Free offer | Catch | Source |
|---|---|---|---|
| Dreamina (ByteDance) | Free daily credits; Seedance 2.5, 2.0 and 2.0 Mini available | Watermark removal is a paid benefit | [6] [7] |
| Runway | 125 one-time credits on the Free plan | Free-plan videos carry a Runway watermark | [8] [9] |
| Kling | Free generation options for eligible users | Free exports generally carry a watermark | [10] |
| Vidu | A set amount of free credits for all users | Amount not stated on the page | [11] |
| Pika | Free plan with no watermark | 0 monthly credits; no commercial licence | [12] |
For a broader comparison see the best free AI video generators.
What it costs once the free credits run out
Price follows resolution and seconds. Through Atlas Cloud, the provider's price endpoint quoted our account $0.29 for a 5-second Seedance 2.0 Fast clip at 720p and $0.87 for 15 seconds on 2026-10-16. A 30-second Seedance 2.5 take at 1080p quoted $17.77. Draft at 720p and render one take at a time; re-render only the take that is wrong.
Mistakes that cost views or the account
- Using a real person's face. TikTok does not allow AI likenesses of anyone under 18 or of private adults without permission, or fake public-figure endorsements, even labelled[1].
- Reposting clips you did not make. Unoriginal or reused material is ineligible for the For You feed[2].
- Franchise characters and props. In our renders the video model's copyright filter blocked famous-character costumes and actor-lookalike faces after the full render.
- Phones and fake interface in the frame. Ask for a phone-camera look and the model may paint a phone case or a streaming bar; forbid it in the prompt.
Where Cast fits
- You want to make TikTok videos from your phone, inside TikTok's own in-app browser, where Cast works. Your first 5-second video is free with no sign-up.
- You want a recurring character without writing prompts: type one line and Cast's language model writes the timed Seedance prompt, rendered at 9:16 on Seedance 2.0 Fast 720p.
- You want to describe your own character in a sentence and pick from four drawn looks (15 credits).
Where it does not:
- Turning your own photo or drawing into a video: Cast characters are drawn from a text description, with no upload.
- Videos over 15 seconds in one render, or editing your own footage: use an editor to join clips.
- Lip-sync to audio you upload: Cast does not take your audio.
People also ask
- What size should TikTok AI videos be?
- Render vertical 9:16. We could not verify official upload dimensions on a TikTok help page. Our own uploads are 720p or 1080p vertical and have had no problems.
- How long should an AI TikTok be?
- Single renders are short: Seedance 2.0 caps a clip at 15 seconds[4], so short clips are the default. If you want TikTok's Creator Rewards, note that it only pays on videos at least one minute long[3].
- Do I have to label AI videos on TikTok?
- Realistic ones, yes; for cartoon or anime content TikTok encourages it[1].
Sources
Claims about other companies come from their own pages, read on the date shown. Products and prices change; check the link for the current version.
- TikTok Help: AI-generated content (read )
- TikTok Community Guidelines: Integrity and authenticity (read )
- TikTok Help: Creator Rewards Program (read )
- BytePlus ModelArk: Seedance 2.0 (read )
- Gemini API docs: Veo (read )
- Dreamina: home page (read )
- Dreamina: pricing (read )
- Runway: pricing (read )
- Runway Help: Free plan details (read )
- Kling AI: AI video generator (read )
- Vidu: home page (read )
- Pika: pricing (read )
Related answers
- What kinds of AI videos do well on TikTok?
- How do I label a video as AI-generated on TikTok?
- Does TikTok allow AI-generated videos?
- Can I run an AI influencer account on TikTok?
- Is there a free AI video generator with no sign-up and no watermark?
- How do I make AI videos for YouTube Shorts?
Part of the Cast answers library (TikTok, Shorts and Reels).
Updated