# Auto Subtitles — Add subtitles to a video automatically on Mac

Turn what's said into captions on the video, burned in for social or as a track you can switch off. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: Video. Runs on your Mac; nothing is uploaded.

Auto Subtitles transcribes the speech in your video on your Mac with Apple's SpeechAnalyzer, splits it into short, readable captions and puts them on the video. Burn them into the picture for Reels, TikTok and Shorts, add a subtitle track people can switch on and off, or get an .srt file as well. Nothing is uploaded.

Page: https://www.onemactools.com/tools/auto-subtitles · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Drop your videos.** Add one or more videos with speech. Or right-click them in Finder and choose Quick Actions › OMT: Add Subtitles, which uses your last settings.
2. **Choose how captions appear.** Burned into the picture for social media, a subtitle track viewers can switch off, or burned in plus an .srt file.
3. **Pick the language and style.** Choose the spoken language, how many words go in each caption, and the text size.
4. **Click Add Subtitles.** The speech is transcribed on your Mac, split into short captions and added to the video. The first time you use a language, macOS may need to fetch its speech model.
5. **Watch the result.** Copies ending in “subtitled” are saved as MP4 in a new dated folder in Downloads › OneMacTools, with the .srt file too if you asked for it. Check them with the Preview (eye) button or Show in Finder. Your originals stay as they were.

## Options
- **Captions:** Burned into the picture (the default) draws the captions onto the video so they show everywhere. Subtitle track (can be switched off) adds captions viewers can turn on and off, and needs FFmpeg. Burned in + .srt file does both: burned-in captions and a separate .srt file.
- **Language:** System language (the default), Chinese, English (India), English (UK), English (US), French, German, Italian, Japanese, Korean, Portuguese or Spanish. Choose the language that's spoken in the video.
- **Words per caption:** 4, 6 (the default), 8 or 10. Fewer words means shorter, punchier captions that change more often, which suits vertical social video.
- **Text size:** From 50% to 200%, 110% by default, for burned-in captions. The size scales with the video, so it looks similar on a phone clip and a 4K video.

## Tips
- Clear speech with little background music gives the most accurate captions. Run Clean Up Audio on a noisy recording first if it struggles.
- For Reels, TikTok and Shorts, use 4 words per caption and a text size of 130–150% so captions are easy to read on a phone.
- Choose Burned in + .srt file if you want to proofread: fix any misheard words in the .srt, then burn it in again with Burn In Subtitles.
- Use the switchable subtitle track for training and longer videos, where viewers may want captions off.
- Set the language rather than relying on System language when the video's language differs from your Mac's.

## Questions
**How do I add subtitles to a video automatically on a Mac?**
Drop the video onto Auto Subtitles, choose the language and click Add Subtitles. The speech is transcribed on your Mac and captions are added to a new copy of the video.

**Which languages does Auto Subtitles support?**
English (US, UK and India), Spanish, French, German, Italian, Portuguese, Japanese, Korean and Chinese, or your Mac's system language if on-device transcription supports it.

**Should I burn captions in or add a subtitle track?**
Burn them in for Instagram, TikTok and Shorts, which don't show separate subtitle files. Use a subtitle track for videos where viewers might want to turn captions off.

**How accurate are the captions?**
Clear speech is usually transcribed well, but names, jargon and noisy recordings can be misheard. Choose Burned in + .srt file so you can correct the text and burn it in again with Burn In Subtitles.

**Can I get an SRT file for YouTube?**
Yes. Choose Burned in + .srt file, and upload the .srt to YouTube as a subtitle file. For the .srt alone, use Transcribe with Subtitles (SRT).

**Why does it say no speech was found?**
The video has no audible speech, or it's in a different language from the one selected. Check the Language setting and try again.

**Does it need an internet connection?**
Transcription runs on your Mac. The first time you use a language, macOS may download its speech model, after which it works offline.