Subtitle Sync Shifter
Open Sync ShifterThe Problem
You load a subtitle file and every single line is off — either appearing a few seconds before the character speaks, or lagging behind so you read the line just as the scene cuts away. The offset is consistent throughout the entire file.
This happens constantly. Subtitle files are created for a specific video release. When a film is re-encoded, released in a different region, or downloaded from a different source than the subtitles, the audio track starts at a slightly different point in time. Every cue is wrong by the same constant amount.
Opening a text editor and manually adjusting hundreds of timestamps is not a realistic option.
How the Sync Shifter Solves It
The Sync Shifter adds (or subtracts) a fixed number of seconds from every timestamp in your SRT file at once. You enter one number — the offset — and every cue's start and end time is recalculated instantly. All processing happens in your browser; your file never leaves your computer.
How to Use It
Step 1 — Upload your file
Drag your .srt file onto the upload zone, or click the zone to open a file picker. A live preview of your first few subtitle cues appears immediately below.
Step 2 — Set the shift amount
The shift field defaults to 0.0 seconds. Use the + and − buttons to nudge in 0.1-second increments, or type a value directly.
| Situation | What to enter |
|---|---|
| Subtitles appear too early (you read before the actor speaks) | A positive number, e.g. +2.5 |
| Subtitles appear too late (they linger after the line is spoken) | A negative number, e.g. -1.8 |
The preview panel updates in real time as you change the value — you can verify the new timestamps before downloading.
Step 3 — Download
Click Download Shifted File. Your browser saves the adjusted SRT with the same filename.
Batch Mode
If you have a whole series — ten episodes each with its own subtitle file, all off by the same amount — enable batch mode by checking the toggle at the top of the page before uploading. Select up to 50 .srt files at once. All are processed with the same offset and downloaded together as a single ZIP archive.
Tips
- Finding the right offset: Pause your video on a line with a clear audio cue (a door knock, the first word of a sentence). Note the video timestamp. Find that cue's timestamp in the SRT. The difference is your shift amount.
- Negative timestamps: If your shift pushes any cue before
00:00:00,000, those entries are clamped to zero so the output stays valid. - This only works for constant offsets. If subtitles are correct in some sections and wrong in others, use the Partial Sync Shifter instead.