Caption tracks for YouTube
YouTube accepts SRT, SBV and WebVTT caption files. Upload the SRT next to your video and viewers can switch the subtitles on or off.
Timed subtitle files
Subtitles you can upload anywhere
The generator writes numbered, timed subtitle lines from the speech in your video. Download them as SRT or VTT for YouTube, Vimeo or a video editor, or style them and burn them into the picture.
Related use cases
The quick answer
Open the Auto Caption subtitle generator, drop the video, let it transcribe, correct the lines, then press SRT or VTT in the Export panel. For subtitles on the picture, pick a style and press Render MP4.
4 steps
How to generate subtitles for a video
- 01
Choose the video
Drop an MP4, MOV or WebM up to 30 minutes long. Leave the language on Auto-detect, or pick it if the clip opens with music.
- 02
Whisper writes the subtitles
Your browser sends a small compressed copy of the soundtrack to the speech model, never the video. Every word comes back with its own timestamp, and the lines are built from those.
- 03
Check each line
Click a subtitle to jump the video there. Fix a misheard word, adjust the start or end time, or split a line that runs too long.
- 04
Download
Save an SRT or VTT file for your player or upload form, or render an MP4 with the subtitles drawn onto the picture.
Where they go
Where automatic subtitles end up
Videos on your own site
Download the VTT and load it with a track element. Browsers show it in the standard video player with no plugin.
Clips that play muted
For a video that will autoplay without sound, render the subtitles into the MP4. They show up wherever the file goes.
A script for a new voiceover
Export TXT, tidy it, and paste it into our text to speech tool. Or keep the SRT and generate narration that follows the same timing.
The subtitle generator runs on Auto Caption, our free caption site. The details below cover what it costs, what it makes, and when to use which output.
A free subtitle generator, and what free covers
You can transcribe 20 minutes of video a day without an account, or 60 minutes once you sign in. One file can run up to 30 minutes. Minutes are counted per started minute of the file and come back as each use turns 24 hours old.
Only the transcription counts. Editing lines, downloading the SRT again after a fix, and rendering a video on your device are free, and nothing gets a watermark. If all you want is the spoken text as a document, Video to Text uses the same engine with the transcript up front.
Subtitle file or subtitles on the picture?
An SRT or VTT file is a separate track. The player shows it, viewers can turn it off, and you can fix a typo later without touching the video. That's the right choice for YouTube, for your own website, and for anything you might edit again.
Rendering the subtitles into the MP4 makes them part of the image. They show on every app and every phone, sound or no sound, but they can't be switched off, and a change means rendering again. The render runs in your browser and keeps the original audio. If you already have a subtitle file and only need this step, go to Burn Subtitles into Video.
How the AI subtitle generator gets the words
The model is Whisper Large V3 Turbo, running on Groq. It returns a time for every single word, which is why the lines start and stop close to the speech instead of in fixed chunks. Vertical videos get shorter lines by default so they fit a phone screen, and you can change the line length in the Layout panel afterwards.
Clear speech near the microphone comes back almost clean. Background music, people talking over each other and rare names cause most of the errors, so plan on a quick read before you publish. Search finds a word across all the lines, and Undo covers anything you change. When you're done, Caption QA will flag lines that flash past too quickly, and Subtitle Converter changes the file format if an upload form wants something else.
Free on Auto Caption
Ready to try it on your own video?
Open the free editor on Auto Caption, drop your file, and download the result in a few minutes.
Generate subtitles
Opens auto-caption.app
FAQ
Subtitle Generator FAQs
01 How do I add subtitles to a video for free?
Open the subtitle generator on Auto Caption and drop the video. Transcription is free for 20 minutes a day without an account and 60 minutes a day when you sign in. Downloading the SRT or VTT and rendering an MP4 cost nothing extra, and there is no watermark.
02 Is my video uploaded?
No. The browser opens the video on your device and pulls out a compressed mono audio track. Only that audio goes to the speech model. We keep a usage record (length and time) for the daily allowance, not the audio or the subtitles.
03 Which languages can it subtitle?
Whisper Large V3 Turbo handles 50+ languages and detects the spoken one by itself. The subtitles come out in the language that was spoken. It does not translate.
04 Does it mark who is speaking?
No. You get the words in order, with timing. If you want speaker names in the subtitles, type them into the lines while you review.
05 I already have an SRT file. Can I use it?
Yes. Drop it in with the video and the transcription step is skipped, so it uses none of your minutes. To change the file without the video, use the Subtitle Editor.
06 Can it make subtitles from an audio file?
Yes. MP3, M4A and WAV transcribe the same way. With audio there is no picture to draw on, so you get the files (SRT, VTT, SBV, TXT) but no MP4.
Still wondering? Get in touch →
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