Free tool: Captions and audio

Subtitle and caption generator for video

Drop in a video or audio clip. An open-source Whisper speech model transcribes it in your browser and gives you timed captions as SRT or WebVTT.

Runs entirely in your browser. Your file is never uploaded: the open-source model is downloaded once to your device and does the work locally. No signup needed.

How to use it

  1. 1Choose a video or audio file (MP4, MOV, WebM, MP3, WAV or M4A, up to 10 minutes).
  2. 2Pick the spoken language, or leave it on English, and start. The first run downloads the model.
  3. 3Review the captions, then download SRT or VTT and import them into your editor or upload them to YouTube.

About this subtitle generator

Most viewers watch short-form video with the sound off, so captions are not optional. This tool writes timed captions for you using the open-source Whisper speech model running on your own device through WebAssembly or WebGPU, so the file never leaves your computer.

Captions are split into readable lines of about 42 characters, the common subtitle guideline, and exported as SRT (for desktop and mobile video editors, Premiere Pro, DaVinci Resolve and YouTube uploads) or WebVTT (for web players). Short clips up to 10 minutes work best; the first run downloads the model, about 80 MB, and later runs reuse it.

Whisper is accurate but not perfect. Read through the captions before you publish and fix names and jargon in the text box; the timings are kept when you edit.

Frequently asked questions

Is my video uploaded anywhere?
No. The audio is decoded and transcribed in your browser. Only the open-source model files are downloaded from a public CDN.
Which subtitle formats can I download?
SRT and WebVTT. SRT is accepted by Premiere Pro, DaVinci Resolve, Final Cut (via import), most mobile editors and YouTube. VTT is the format HTML5 video players use.
How long can the video be?
Up to 10 minutes and 200 MB per file. Transcription speed depends on your device: a recent laptop handles a one-minute clip in well under a minute.
Can I get word-by-word animated captions?
This free tool gives standard subtitle lines. Menivor's video tool burns in word-by-word karaoke captions timed to each spoken word on the finished video.
Which languages are supported?
Whisper is multilingual. Choose the language from the menu for the best accuracy; English is the most accurate.

More free tools

Video to textTurn a video or voice recording into a plain-text transcript you can copy, edit, or repurpose into posts, scripts and show notes.SRT to VTT converterPaste or upload an SRT or VTT file and convert it to the other format instantlySubtitle shifterSubtitles out of sync? Move every cue earlier or later by a fixed offset, or stretch timings to fix drift between 23.976, 24, 25 and 30 fps versions.AI voiceover generatorPaste a script, pick a voice and download a natural-sounding voiceover as WAV, generated on your device with an open-weight text-to-speech model.

Guides and video makers

Add captions to videoKaraoke caption generatorHow to add karaoke captions to videos

See all free video tools.

Skip the busywork: get finished videos

Paste a link or type a topic. Menivor writes the hook and script, records the voiceover, adds footage and word-by-word captions, and renders ready-to-post vertical videos in 1080 x 1920.

See pricing