Free tool
Turn a YouTube video into Shorts
Paste the link to any public YouTube video up to 30 minutes long. We find its best moments, cut each one to 9:16, add captions and score it, so you know which Short to post first.
No credit card needed
Works with
- YouTube videos
- YouTube live replays
- MP4, MOV and other video files
- Up to 30 minutes long
How it works
1
Copy the video's link
Any public video, or a live stream replay. Your own channel or one you have the rights to.
2
Paste it above
We listen to the whole video and pick the 5–10 moments most likely to hold attention.
3
Download your Shorts
Each one is vertical, captioned and ready to upload. Post the highest score first.
Everything you need to turn one video into many clips
Paste a link and Onyx finds the moments worth posting, cuts them to vertical, adds captions and tells you which ones should do best.
Find a specific moment
Tell the AI what you're after, like “the money advice” or “the funniest stories”, and it looks for those moments first.
Virality score with a reason
Every clip gets a score out of 100 and one plain sentence on why it should work, so you know what to post first.
Captions that pop
Captions timed to every word, in 5 styles: from bold with the spoken word lit up, to plain and quiet.
Smart framing
Face tracking follows the speaker. Split screen puts a facecam over the action, and Fit shows the whole picture on a blurred background.
Remove pauses
Long silences between words are cut down to a short breath, and the captions stay in sync.
Paste a link or upload
YouTube videos, finished live streams and your own video files, up to 30 minutes long.
Clips as they finish
Watch and download each clip the moment it's ready, while the rest are still being made.
Private by default
Only you can see your videos and clips, and the files delete automatically after 7 days.
Questions
- Will the Shorts fit YouTube's format?
- Yes. Every clip is vertical 9:16, and you can choose clips under 30 seconds, 30 to 60 seconds or 60 to 90 seconds.
- Can I use someone else's video?
- Only if you have the rights to it. Our Terms of Service ask you to submit only videos you own or have permission to use.
- Is it really free?
- Free to try: 2 videos a month, no credit card. Free clips carry a small watermark. Starter removes it and gives you 10 videos a month for $5.