Subtitle Shifter
Shift, resync and convert SRT and WebVTT subtitle timings.
Subtitles That Finally Match The Voices
Subtitles that appear consistently early or late just need shifting: enter the delay and every line moves, optionally from a chosen line onwards. Subtitles that start right but drift further out as the film goes on were made for a different cut or frame rate — sync them with two reference lines and everything in between is stretched to fit.
A frame-rate option converts between the common 23.976, 24, 25, 29.97 and 30 fps, and any adjustment can be saved as SRT or WebVTT, the format HTML5 video and YouTube use. Formatting tags can be stripped for players that show them literally.
Key features
- Shift all lines, or from a line onwards.
- Two-point sync that fixes drift.
- Frame-rate conversion between common rates.
- SRT ↔ WebVTT conversion.
- Before / after preview of the first lines.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Subtitle Shifter
- Drop in the subtitle file
Or paste its contents. - Choose shift, sync or frame rate
Shift for constant delay, sync for drift. - Enter the correction
Watch the before/after columns update. - Download
In the same format, or converted.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Converters |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
How do I know how much to shift?
Find a clear line of dialogue, note when it is spoken and when its subtitle appears. The difference is the shift: positive if subtitles should appear later, negative if earlier.
My subtitles drift further out over time — why?
They were timed for a different version: another frame rate (often 25 fps PAL versus 23.976 fps) or a cut with scenes added or removed. Use two-point sync with a line near the start and one near the end.
What is the difference between SRT and VTT?
Both are timed text. SRT numbers each cue and uses commas in timestamps; WebVTT starts with a WEBVTT header, uses full stops and supports positioning. HTML5 video requires VTT.
Will this change the subtitle text?
No — only the timings, unless you choose to remove formatting tags. Line breaks and characters are kept exactly.
Can I shift just part of the file?
Yes. Set “From cue number” and only that line and the ones after it move — useful when an ad break or a missing scene throws the second half out.