When subtitles appear before the speaker or arrive after the line is spoken, the file usually needs a global timing offset. You can fix subtitles that are out of sync by measuring the difference, applying a positive or negative shift, and checking the result in the video player. The subtitle sync tool supports SRT and VTT and keeps the corrected file in your browser.
Decide whether the subtitles are early or late
Play a section with a clear spoken word or visible action. Compare the moment the line appears with the moment it should be heard. If the caption appears two seconds before the speech, it is early. If it appears two seconds after the speech, it is late.
Write down the offset before editing. A consistent difference across the whole video normally needs one global shift. If the timing drifts gradually, the source may have a frame-rate or duration mismatch and a simple delay will not fix every cue.
How to sync subtitles online
1. Open the subtitle sync tool
Open the subtitle time shifter and upload the SRT or VTT file. The format is detected automatically, and the original format is used for the download.
2. Enter the timing offset
Use a positive value to move subtitles later in the video. Use a negative value to move them earlier. For example, if subtitles appear two seconds early, start with 2; if they appear two seconds late, start with -2.
Small offsets such as 0.3 or 1.5 seconds can help when the mismatch is less than a full second. Apply the smallest value that makes the first few cues line up instead of making a large change and trying to correct it later.
3. Check the beginning, middle, and end
Download the shifted file and test a scene near the beginning, one in the middle, and one near the end. If all three locations are aligned, the global offset was probably the right fix. If the beginning is correct but the end drifts, investigate frame rate, video edits, or a missing section in the source.
4. Keep the original and publish the corrected copy
Save the adjusted file with a new name, such as episode-01-synced.srt. Keep the original subtitle file so you can try a different offset or create a VTT version later.
Common subtitle sync problems
The first cue starts before zero
A negative shift can move an early cue below the beginning of the video. The tool clamps negative timestamps at zero so the resulting SRT or VTT remains valid. Check the first few lines after downloading, especially when using a large negative value.
Only some lines are out of sync
A global shift moves every cue by the same amount. If only one scene is wrong, edit that section separately or split the file before applying a local correction. Do not use a whole-file offset when the error changes at a cut.
The subtitle format is not accepted
If the player expects WebVTT, use the SRT to VTT converter after timing is correct. If an editor expects SRT, use the VTT to SRT converter.
Two subtitle parts need different offsets
Shift each part independently, then use the subtitle merger to combine them. Check the order and the timeline after merging because the merger preserves the cue times you provide.
FAQ
How do I fix subtitles that are out of sync?
Measure the difference between the spoken line and the caption, apply a positive or negative offset with the subtitle sync tool, then test the beginning, middle, and end of the video.
Should I use a positive or negative subtitle delay?
Use a positive delay when captions are early and need to appear later. Use a negative delay when captions are late and need to appear earlier.
Why do subtitles drift over time?
Drift can come from a different frame rate, a different video cut, or a source with a different duration. A single offset only fixes a constant difference; drift may require retiming or a matching video release.
Can I sync both SRT and VTT files?
Yes. The tool accepts both formats and preserves the input format in the downloaded file.
Continue editing subtitles
Start with the subtitle sync tool, convert to the format your player needs with SRT to VTT or VTT to SRT, and merge corrected parts with the subtitle merger.