Shift subtitles and convert between SRT and WebVTT

Understand the settings

A subtitle cue pairs text with a start and end time. SRT commonly uses a comma before milliseconds; WebVTT uses a period and a WEBVTT header. Renaming the extension alone does not perform this conversion. This tool parses the cues and writes the chosen syntax.

A positive shift makes every cue appear later. A negative shift makes every cue appear earlier. A constant shift can fix a constant offset, but cannot correct drift that grows through the video. Drift can come from different edits or frame-rate conversions and requires a separate timing adjustment.

The tool handles ordinary text cues. VTT styling, positioning, regions and original cue identifiers are not preserved. Inline tags remain unless you choose to remove them. Removing tags does not translate text or decode every possible subtitle markup convention.

Step by step

1. Load an SRT/VTT file or paste its text.
2. Choose the output format and a shift in seconds. Use 0 for format conversion only.
3. Optionally remove inline markup, then process.
4. Read the overlap count and inspect the result. Download it and check the beginning, middle and end against the video.

Move subtitles half a second later

A cue originally at 00:00:01.000–00:00:03.000 becomes 00:00:01.500–00:00:03.500 with a shift of +0.5. To move it earlier by the same amount, use -0.5. A shift that moves any cue before zero is rejected.

Limits and what to check

• Up to 1,000,000 characters and 10,000 cues. Input files should be UTF-8.
• There is no speech recognition, translation, OCR or automatic synchronization to audio.
• Overlapping cues are reported, not automatically deleted or reordered; overlapping speakers can be intentional.
• Text stays in the browser. The original file is not modified.

Troubleshooting