How to edit subtitles
- Open your subtitle file (.srt or .vtt), and optionally the video it belongs to. Or press Start empty to write subtitles from scratch.
- Edit any cue's text and times directly in the list. Problems are highlighted: cues that overlap, end before they start, have lines over 42 characters or go by too fast to read.
- With a video open, play it and watch the subtitles appear on the picture. Select a cue and use Set start and Set end to snap its times to the video, or press Cue at current time (Alt+N) to add a new one.
- If every subtitle is early or late, use Shift. If they drift further out of sync over time, use two-point sync with the correct times of the first and last line.
- Press Sort & fix to tidy up, then download as SRT or WebVTT.
Good subtitle practice
Readable subtitles follow a few rules used by broadcasters and streaming services: at most two lines, around 42 characters per line, a reading speed below about 17 to 21 characters per second, and at least a second on screen. Break lines at natural phrase boundaries, and leave a tiny gap between consecutive cues so the viewer notices the change. SRT is the most widely supported format (YouTube, Vimeo, Facebook, LinkedIn, Premiere, DaVinci Resolve, VLC), while WebVTT is the web standard used by HTML5 video players.
Out-of-sync subtitles are usually caused by a different video release: a constant offset is fixed by shifting, while drift (for example 25 versus 23.976 frames per second) needs a proportional stretch, which two-point sync does for you. Your work is saved in this browser as you go, and nothing is uploaded.
How do I fix subtitles that are out of sync?
If they are off by the same amount throughout, shift them later or earlier. If the gap grows over time, use two-point sync with the correct times of the first and last cue.
What is the difference between SRT and VTT?
Both store timed text. SRT uses commas in times and numbered cues; WebVTT starts with "WEBVTT", uses dots and supports styling. Most platforms accept both.
Is my work saved?
Cues are saved in this browser automatically, so you can close the tab and continue later. Download the file to keep it permanently.
Are my files uploaded?
No. The video and subtitles are opened locally in your browser.