01
Choose a file
Select a video or audio file from your device. It never leaves your browser.
Video to captions
Create your subtitle file
Runs on your device
Drop a video or audio file hereor click to browse · up to 2 GB / 2 hours
Upload a file or paste a direct media URL to begin.
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Protected video?
Caption the video from its open browser tab.
YouTube and protected Vimeo or Zoom links cannot be imported directly. Our companion browser extension will capture the audio only after you open the video and start it yourself, then generate captions on your device. It will not bypass sign-ins, passwords, or viewing permissions.
Browser extension coming next
How it works
Captions in three simple steps
02
Generate captions
A compact Whisper model transcribes the audio locally on your computer.
03
Download
Save the result as SRT, WebVTT, or plain text—free and without an account.
Why local processing?
Private by design. Cheap enough to stay free.
Most transcription sites upload your media to a remote server. This tool uses your browser's WebGPU or WebAssembly support instead. That protects private recordings and lets us offer the core tool without usage credits.
No uploadsYour video remains on your device.
No accountOpen the page and start working.
Reusable modelYour browser caches the AI model after the first run.
Standard formatsExport SRT, VTT, or TXT files.
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Practical guides
Browse all guides →Make better captions, one clear step at a time.
Questions
Frequently asked questions
Are my videos uploaded?
No. Decoding and transcription happen inside your browser. We do not receive or store your media.
Why does the first transcription take longer?
Your browser must download the speech-recognition model once. It is normally cached for later visits.
Which files work?
MP4, WebM, MP3, WAV, M4A, and other formats your browser can decode, up to 2 GB and two hours. CaptionKite reads large local files incrementally; transcription memory depends on audio duration rather than video resolution. Chrome or Edge provides the best compatibility.
Can I paste a video URL?
Yes. The tool processes direct media links and authorized Vimeo or Zoom download links. YouTube, sign-in pages, and links whose owners disabled access are routed to the companion browser extension.