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Runs in your browser · nothing uploaded

Add subtitles to a video online, free

Drop in a clip and Just Captions transcribes it and burns in clean subtitles — right here in your browser, on your device. No sign-up, no upload, no editing skills.

Drop a clip and add subtitles free — right here
mp4 · mov · first 60s
or

On-device. Nothing uploaded. Engine downloads once.

How it works

Three steps, no account

  1. Drop in a clipChoose an MP4 or MOV from your device. The first time, a small on-device engine downloads to your browser — after that it's cached.
  2. It transcribes & captionsThe speech is transcribed and clean subtitles are timed and burned in, entirely on your device. Nothing is uploaded.
  3. Download your MP4Preview the result and download a captioned MP4, ready to post to TikTok, Reels or Shorts.
Private by design. Your footage never leaves your browser. There is no server to upload to, no queue, and no account — the captions are generated locally on your own machine.
What you get

Free online vs. the free app

The browser tool is a quick, no-install taste of the engine. The free iOS app removes the limits.

FeatureOnline toolJust Captions app
PriceFreeFree
On-device / privateYesYes
Clip lengthFirst 60 secondsLonger clips
Videos at once1Up to 20 (Batch Mode)
Caption styles1 fixed preset4 readable presets
Edit text · AI Correct—Yes
AI Auto Translate—33 languages
WatermarkSmall watermarkNone
Get the free app
FAQ

About the online tool

Is this online subtitle tool really free?
Yes. You can caption a clip here free, with no sign-up and no card. The engine downloads to your browser once, then runs on your device.
Is my video uploaded to a server?
No. Everything happens in your browser, on your device. Your footage is never uploaded — the transcription and the burned-in captions are generated locally.
What are the limits of the free online tool?
The browser tool captions one clip at a time, trimmed to the first 60 seconds, in a single fixed style with a small watermark. Editing, four caption styles, AI translate, batch of five and watermark-free export live in the free Just Captions iOS app.
What video formats can I use?
MP4 and MOV work best. Drop a file in or choose one from your device, and the tool exports a captioned MP4 you can download.
Captioning guides

Get it right for each platform

Captions for TikTokSafe zones and styling tuned for TikTok.Read →
Captions for Instagram ReelsPlacement that clears the Reels UI.Read →
Captions for YouTube ShortsBurned-in subtitles for the Shorts player.Read →

Subtitles in a minute. That's it.

Free to start, no card, nothing uploaded. Try it above, or get the full app for styles, editing and batch.

Download on theApp Store