Free auto captions
Captions that pop.
Drop a vertical video and get word-by-word captions in the style creators use, burned into an MP4 for TikTok, Reels or Shorts. Fix any word, then download.
Free, no sign-up, no watermark. Your video stays on this device; only its sound is sent to be transcribed, and it is not kept.
Pick a style
Big words, the one being said in yellow
Where on screen
Your video stays with you
How it works
- 1
Your device
Takes the sound out of the video and shrinks it to a small voice-only file.
- 2
Cloudflare Workers AI
Whisper writes down each word with its timing. The sound is not stored, by us or by it.
- 3
Your device
Draws your style on every frame and makes the MP4. No upload, no watermark.
Only need it smaller? The free video compressor fits any video to each platform’s limits.
Writing the post text too? The free post preview shows it on all 9 platforms.
Questions
Auto captions questions
How do I add auto captions to a video for free?
Drop the video here and press Make captions. In a few seconds every word appears with its timing. Pick a style, fix any word, pick TikTok, Reels or Shorts, and download the MP4 with the captions burned in. No account and no watermark.
Is my video uploaded?
No. Your browser takes the sound out of the video and sends only that, as a small voice-only file, to Cloudflare Workers AI, where OpenAI’s Whisper model writes down the words. The sound is used for that one request and not kept. The video itself never leaves your device: the captions are drawn and the MP4 is made in your browser.
Is there a limit?
5 videos a day each, up to 3 min long. Writing down the words costs us a little (about 0.15 cents for a 3 minute video), so there is a daily cap to keep it free for everyone. Burning in the captions has no limit.
Which caption style is best for TikTok and Reels?
Pop and Highlight are the bold, word-by-word looks most creators use: big words, the one being said lit up. Subtitle reads best for longer talks and interviews. All of them sit above the part of the screen TikTok, Reels and Shorts cover with the caption and buttons, unless you move them.
Can I get an SRT file?
Yes. After you make the captions, Download SRT gives you a standard subtitle file to upload to YouTube, LinkedIn or Facebook instead of burning the words in.
Which languages work?
Whisper recognises about 100 languages and picks the one it hears. Captions use the Inter and Inter Tight fonts, which cover Latin-script languages; other scripts show in your device’s own font.
Does it work on an iPhone or Android phone?
Yes, in Safari 16.4 or newer and in Chrome. Writing down the words happens on Cloudflare, so it is quick anywhere; drawing the captions into the video uses the phone’s own video chip and takes about as long as the video, a little longer on older phones.
The page uses Mediabunny, an open-source video library under the Mozilla Public License 2.0; its source is at github.com/Vanilagy/mediabunny.
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