Upload your video
Choose a video from your phone or computer. MP4, MOV, and WebM all work.
Refract Creators / Auto caption generator
Free tool
Free auto caption generator, no watermark
Upload a video and Refract writes what you say on it, in the font and caption style you pick. Fix any word, then save the captioned video to your phone. Free with an account, and your video file never leaves your device.
How it works
Pick a look
Choose a font, a caption style, a colour, and where the captions sit.
Export and post
Fix any word, then save the captioned video or share it straight to your app.
What’s free, and what Pro adds
10 videos a day
Videos up to 3 minutes, 8 fonts, and 4 caption styles. Exported at 720p with no watermark.
Fix any word
Edit the text before you export, pick 1 to 5 words per caption, and download an .srt subtitles file too.
More looks, sharper video
12 more fonts, 6 more styles like Karaoke and Pop, any colour, videos up to 15 minutes, and 1080p export.
Your video stays on your device
Refract never uploads your video. Your browser takes the sound from it and sends only that sound to the speech-to-text AI. The captioned video is made in your browser, and Refract doesn’t keep the sound or the text. Read the privacy policy for the details.
How to make captions people can read
Most people scroll with the sound off, so your captions do the talking. These habits make them easy to follow.
- Keep each caption short.
Two or three words at a time is easy to read at a glance. Refract lets you choose 1 to 5 words per caption.
- Keep them out of the buttons.
TikTok, Reels, and Shorts cover the bottom and right side of the screen. Put captions in the middle or a little above the bottom.
- Use a bold, simple font.
Heavy fonts like Montserrat or Anton stay readable on any background.
- Check the words before you export.
Names and slang are the words speech-to-text gets wrong most often. Fix them in Edit captions.
- Match the style to the video.
Clean suits talking videos. Highlight helps the key word stand out in tutorials and lists.
Questions
Is the auto caption generator free?
Yes. A free account captions up to 10 videos a day, up to 3 minutes each, with 8 fonts and 4 styles. There’s no watermark.
Does it add a watermark?
No. The exported video has no Refract logo or watermark, on the free plan or Pro.
Is my video uploaded?
No. Your browser takes the sound from the video and sends only that to the AI that writes the captions. The video file stays on your device.
Can I edit the captions?
Yes. Fix any word before you export, and click a time to jump to that moment in the video.
Can I get an .srt subtitles file?
Yes. Download an .srt file to upload to YouTube or any editor that accepts subtitles.
Which languages work?
The captions come from Whisper, an open speech-to-text model made by OpenAI, running on Cloudflare. It works best with clear speech in English and handles many other languages too.
Does it work on my phone?
Yes, in a modern browser on iPhone or Android. On a phone, Save to Photos or share sends the finished video straight to your camera roll or app.
Caption your next video free.
Create a free account and caption up to 10 videos a day. No card, no watermark.