Resync WebVTT captions for web video
Use this page when a VTT file is structurally valid but every cue appears too early or too late in an HTML5 player, course platform, product demo, or documentation video. Enter a positive offset to delay captions or a negative offset to make them appear earlier.
The tool keeps the output as WebVTT, so you can download a browser-ready file after the timing correction. It is intended for subtitle timing, not for changing the spoken text or rewriting cue content.
Understand what changes in the output
The converter parses WebVTT cue ranges, shifts the start and end times, and writes a clean WEBVTT file with dot-separated milliseconds. Any cue that would move before zero is clamped to the start of the video.
Cue settings such as position or line placement are removed during normalization. That tradeoff keeps the result simple and compatible, but highly styled VTT files should be tested carefully after conversion.
When one offset is enough
A single offset works well when the whole caption file is displaced by the same amount, such as after a preroll was added, a video intro was trimmed, or captions were exported from a slightly different master.
If the delay changes from scene to scene, a global shift will only fix part of the file. In that case, split the VTT into sections or use a timeline editor that can retime selected cue ranges.
Test in the target player
WebVTT rendering can vary across browsers, embedded players, and learning platforms. After shifting, preview the file in the same player your viewers will use instead of relying only on a text editor.
Check the beginning, middle, and end of the video. If captions wrap differently or lose important placement metadata, adjust the output manually or keep a styled backup of the original VTT.