An SRT file is plain text. Each caption has a number, a start and end time, and one or two lines of words. YouTube reads that structure to show subtitles in time with your video.
This tool builds the file for you from the audio, with short lines that read comfortably, and lets you fix the words before exporting.
SRT file for YouTube: what to know
Short lines read better
The tool breaks captions at about 28 or 42 characters, your choice, so lines are short enough to read on a phone without covering the picture.
If your subtitles look out of sync
Use the subtitle converter to shift the whole file earlier or later by a fixed number of seconds. It only takes a moment to fix a constant offset.
SRT or VTT
YouTube accepts both. SRT is the simplest and the most widely supported. VTT is the web standard and also works well.
How to use
- Add your video or audio. Drop an MP4, MOV, WebM, MP3 or WAV file into the tool. Files up to about 10 minutes work best.
- Pick a language and a speed. Leave the language on auto-detect or choose yours. The page shows an estimated wait for each model size, measured on your device after the first run.
- Fix any words. Read through the generated lines and correct names, brands and jargon. If you only change spelling, the word timing stays exact.
- Export or burn in. Download an SRT or VTT to upload in YouTube Studio, or choose a caption style and create a new MP4 with the captions drawn onto it.
Limits and good to know
- Works best on clips up to about 10 minutes. Longer files use a lot of memory on phones.
- The first run downloads the speech model once, then your browser keeps it.
- Burning captions in records the video in real time, so keep the tab open and visible until it finishes.
FAQ
Where do I upload the SRT?
In YouTube Studio, open Subtitles, choose the video and language, then Add and upload the file with timing.
Can I edit the SRT afterwards?
Yes. Edit the text in the tool before exporting, or use the subtitle converter to shift timing or clean up an existing file.
Is my video uploaded to create the file?
No. The audio is processed on your device.
Is the caption generator free?
Yes. There is no sign-up, no watermark and no daily limit.
Is my video uploaded?
No. The speech model runs in your browser on your own device.
Which file does YouTube want?
Download the SRT or VTT and upload it under Subtitles in YouTube Studio. Both are accepted.