---
title: "Subtitle Sync – Shift or Stretch SRT Timing | sync.video"
description: "Subtitles out of sync? Shift an SRT or VTT file, stretch it with two points, change its frame rate or match it to the speech automatically. Free, no upload."
url: https://sync.video/subtitle-sync
---

1. [Home](https://sync.video/)
2. [Fix audio sync](https://sync.video/fix-audio-sync)
3. Subtitle sync

Free · runs in your browser

# Sync subtitles to your video

Move every line earlier or later, fix subtitles that drift with two sync points or a frame-rate change, or let the video’s own speech line them up.

To sync subtitles, open the subtitle file here with its video, then either move every line with **Earlier** and **Later**, type a shift in milliseconds, or press **Auto sync** to match the lines to the speech it hears. When the lines are right at the start but wrong by the end, use **Two-point sync**: set one line near the start and one near the end, and the timings between them are stretched to fit. **Download subtitles** saves the corrected file.

SRT, VTT and ASS or SSA files all open, and the video is optional: without it you can still shift or convert the timing by a known amount. Like every tool here, it runs in your browser, so the film and its subtitles never leave your device. If the problem is the film’s sound rather than its subtitles, the [audio sync fixer](https://sync.video/fix-audio-sync) is the tool you want.

Subtitle sync: the lines are shifted, or stretched between two points, until each line starts when its words are spoken.

## How to sync a subtitle file

1. ### Open the subtitles and the video
Drop the SRT or VTT file onto **Drop subtitles to sync**, then add the video when asked (**Now add the video**), or press **Sync without the video** if you only need a fixed shift.
2. ### Try Auto sync
Press **Auto sync** (A). It listens for speech in the video and moves the lines to match, then shows how far it moved them and a confidence of High, Medium or Low. **Undo** (Ctrl/⌘+Z) puts them back.
3. ### Or fix it by hand
Use **Earlier** and **Later** (\[ and \], 100 ms; Shift for 1 s; Alt for 10 ms) or type the **Shift in milliseconds**. For drift, pause where a line should start, pick it in the list and press **Set this line to now** (L), once near the start and once near the end, then **Apply two-point sync**.
4. ### Download subtitles
Choose the **Format** (SRT or VTT; ASS stays available for ASS files) and press **Download subtitles** (D).

## Three kinds of subtitle sync problem

__What you see, and the fix__
| What you see                                   | Cause                                                                       | Fix                                                                                                              |
| ---------------------------------------------- | --------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| Every line is early or late by the same amount | The subtitles were timed to a version with a different intro, logo or start | A shift: **Earlier**, **Later** or **Shift in milliseconds**                                                     |
| Fine at the start, worse and worse later       | Made for a different frame rate, or a different speed of the film           | **Frame rate** under **More options**, or **Two-point sync**                                                     |
| Fine for a while, then suddenly off            | A scene was cut or added in your version                                    | Split the problem: sync up to the cut, then shift the rest in a player; one straight-line fix can’t follow a cut |

### Frame-rate conversions

Films shot at 24 frames per second are often broadcast in Europe at 25, which makes them about 4 % shorter. Subtitles timed for one release then drift steadily against the other. The **Frame rate** presets convert between 23.976, 24, 25 and 29.97 in one step.

## How Auto sync works

Auto sync listens to the video’s soundtrack for speech: the energy in the voice band, measured against a background level that adapts to music and noise. It then slides the subtitle timings past that speech pattern to find where the lines and the talking overlap best, tries the common frame-rate speeds too, and finally checks several stretches of the film to catch a slow drift. It all runs in a background worker on your device.

* It needs dialogue. A film that is mostly music or effects gives a Low confidence.
* It applies one straight-line correction (a shift plus a speed). It can’t repair lines out of order or a version with re-cut scenes.
* **Search range** under **More options** chooses ±1 minute (fast) or ±10 minutes (for subtitles that start far away).

## Formats and what is kept

* **SRT** and **WebVTT**: every line, its text and its styling tags are kept; only the times change.
* **ASS and SSA**: times are shifted and all styling is kept. Converting ASS to SRT or VTT drops its override tags.
* Files in older encodings are read as Windows-1252 when they aren’t valid UTF-8, and saved as UTF-8; the page says when that happens.
* Lines that would end before 0:00 after a shift are left out, and the page says how many.
* Frame-based MicroDVD `.sub` files and image subtitles (from DVDs and Blu-rays) aren’t supported.

## Doing it in a player instead

Most players can delay subtitles for one viewing. In VLC, the G and H keys move subtitles by 50 ms, and **Tools → Track Synchronization** takes an exact value; see the [VLC guide](https://sync.video/vlc-audio-delay). That setting lasts only while the player is open. Fixing the file means it plays right everywhere, on every device and every time.

1. Note the delay that works in the player.
2. Open the subtitles here and type it as the **Shift in milliseconds** (VLC shows seconds: 1.5 s is 1500 ms).
3. Press **Download subtitles** and keep the corrected file next to the video.

## Questions about syncing subtitles

### Why are my subtitles out of sync?

They were timed for a slightly different version of the video: one with a different opening, a different frame rate or a few scenes cut. A shift fixes the first, a frame-rate change or two-point sync fixes the second.

### Can it sync subtitles automatically?

Yes, when you add the video. **Auto sync** matches the lines to the speech it hears and reports how confident it is. Check a few lines in different places before downloading.

### Do I need the video?

No. Without it you can shift the timing by a known amount or convert the frame rate. The video is needed for Auto sync and for watching the lines play in place.

### Which subtitle formats work?

SRT, WebVTT and ASS or SSA. You can save SRT or VTT, and ASS files can be saved as ASS too.

### Will it change the text of my subtitles?

No. Only the times change. Text, line breaks and styling tags stay as they were.

### Are the subtitle file and the film uploaded?

No. Both are read by your browser on your device. Nothing is sent anywhere.

## More in fix audio sync

* [ Fix audio and video out of sync Work out whether the file or the playback is at fault, then fix the delay or measure it. ](https://sync.video/fix-audio-sync)
* [ Fix audio delay in VLC The J and K keys, Track Synchronization and how to save the delay into the file. ](https://sync.video/vlc-audio-delay)
* [ Fix audio that slowly drifts Two sync points stretch the sound so it stays in step from start to end. ](https://sync.video/fix-audio-drift)
* [ Fix streaming audio out of sync One app, one show or every app? Find the cause and the fix for streaming lag. ](https://sync.video/streaming-audio-out-of-sync)
* [ Sync audio and video online Drop one video to fix its delay, or several files to line them up by their sound. ](https://sync.video/)