Loona SRT Subtitle Editor - Fix, Shift & Convert Subtitles Online Free
Downloaded subtitles that show a few seconds before the actor speaks, captions with spelling mistakes, subtitle files in the wrong format for your player - all of these are problems inside the subtitle file itself, and all of them can be fixed by editing that file. Load it below, make your changes in the table, and download the repaired file. Nothing is uploaded anywhere.
How to edit a subtitle file
- Click the box above and choose your .srt or .vtt file - or paste the subtitle text into the box, or press "Load Sample Subtitles" to try the editor first.
- Every cue appears in the table. Type directly into any Start, End or text box to change it; your typing is picked up as you go.
- To resync a whole file, type the shift in seconds (for example 2.5 if captions show 2.5 seconds too early, -2.5 if they show too late) and press "Shift All Cues". To move only part of the file, fill in "From cue #" and "To cue #" and use "Shift Range Only".
- Press "Find Overlaps" to highlight any cue that is still on screen when the next one starts, then "Fix Overlaps" to end each such cue exactly where the next begins.
- Download the repaired file as .srt, or as WebVTT (.vtt) if your player or website needs that format.
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Frequently Asked Questions
Is the Subtitle Editor free?
Yes. It is completely free with no sign-up, no watermark and no limit imposed by us.
Are my subtitle files uploaded to a server?
No. Your subtitle file is read and edited 100% inside your browser. It never leaves your device, and nothing is stored anywhere.
Can this tool create subtitles automatically from a video or audio file?
No. This tool edits subtitle files that already exist (SRT and WebVTT). Turning speech into captions automatically requires speech-recognition AI, which this tool does not do - it is an editor, not a transcriber.
What is the difference between SRT and WebVTT?
SRT (SubRip) is the most widely used subtitle format - YouTube and most video players accept it. WebVTT is the web standard used by HTML5 video players in browsers. They contain the same cues; VTT writes the decimal separator as a dot instead of a comma and starts with a WEBVTT header line. This tool opens and saves both, so converting is just a download in the other format.
Why are my subtitles slightly early or late against the video?
Usually the subtitle file was made for a different cut of the video - a version with a longer intro, a removed scene, or a streaming release that differs from yours. If every caption is off by roughly the same amount, enter that amount in the shift box (positive makes captions later, negative makes them earlier) and shift all cues in one click. If captions start in sync but drift further apart as the video plays, that is a frame-rate mismatch (for example 23.976 fps subtitles against a 25 fps video) - a constant shift cannot fully fix gradual drift.
How it works
Your subtitle file is plain text: a list of cues, each with a start time, an end time and one or more lines of text. This editor reads the file with your browser, turns every cue into a row of the table, and does simple arithmetic on the timestamps - stored internally as exact milliseconds - whenever you shift, sort or repair cues. The downloads are then written back out as standard SRT or WebVTT text, generated on your device. Because everything is text and arithmetic, the tool works offline once the page has loaded, and handles files with thousands of cues.
Worked example
You download subtitles for a film, but every caption appears 2.5 seconds before the line is spoken - the file was made for a release without the studio intro. You load the .srt here, type 2.5 in the shift box and press "Shift All Cues": a cue that read 00:00:07,000 --> 00:00:09,500 now reads 00:00:09,500 --> 00:00:12,000, and every other cue moves by the same 2.5 seconds. You download the .srt and the captions line up with the speech.
The same idea fixes a single bad section: if only the cues after an inserted scene are wrong, shift just that range by the length of the scene.
More questions
Can I use the downloaded file on YouTube?
Yes. YouTube accepts .srt uploads directly (Subtitles > Add language > Upload file). Download your edited file as .srt here and upload it - the timings and text you set are exactly what YouTube will show.
What exactly does "Fix Overlaps" change?
It looks at each pair of neighbouring cues. If a cue's end time is later than the next cue's start time, the first cue's end is pulled back to exactly the next cue's start, so only one caption is ever on screen at a time. It never moves a start time and never deletes text.
Which subtitle formats can I open?
SRT (.srt) and WebVTT (.vtt). Other formats such as SSA/ASS or TTML are not supported by this editor - most tools that produce them can export an SRT copy, which you can then edit here.
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