BYTETOOLS

Subtitle Timing Shifter

Resync SRT and VTT subtitles by shifting every timestamp, rescaling for a different frame rate, or fitting a correction from two known times.

Drop a .srt or .vtt file here or click to browseThe file is read in your browser and never uploaded

What is the Subtitle Timing Shifter?

Subtitle Timing Shifter fixes subtitles that do not line up with your video. Use a fixed offset when the whole file is early or late by the same amount, rescale by frame rate when subtitles were timed for a 25 fps copy but your video runs at 23.

  • Fixed offset in seconds or milliseconds, forward or backward
  • Frame-rate rescaling between 23.976, 24, 25, 29.97 and 30 fps
  • Two-point linear fit that corrects gradual drift
  • Negative timestamps clamped to zero and counted
  • Warns about cues that now overlap the previous one
  • Reads and writes both SubRip and WebVTT

How to use the Subtitle Timing Shifter

  1. 1

    Paste your subtitles, or drop a .srt or .vtt file onto the drop zone.

  2. 2

    Pick a correction method: fixed shift, frame-rate rescale, or a fit from two known times.

  3. 3

    Enter the shift amount, the two frame rates, or the two pairs of current and correct times.

  4. 4

    Review the speed factor, constant shift and any clamping or overlap warnings.

  5. 5

    Copy the retimed subtitles or download them as .srt or .vtt.

About the Subtitle Timing Shifter

Subtitle Timing Shifter fixes subtitles that do not line up with your video. Use a fixed offset when the whole file is early or late by the same amount, rescale by frame rate when subtitles were timed for a 25 fps copy but your video runs at 23.976, or fit a correction from two cues you have checked by eye when the drift grows through the film.

The two-point method is the one that fixes progressive drift. Give the tool a cue near the start and another near the end, along with the time each one should actually appear, and it solves the straight line through both points and applies it to every timestamp in the file.

Timestamps that would fall before the start of the media are clamped to zero and counted, and overlapping cues are reported so you can spot problems before you save. Everything runs locally in your browser and no file is ever uploaded, so unreleased footage and client work stay on your own machine, and the speed factor and constant shift are both shown so you can see exactly what was applied.

Frequently asked questions

How do I fix subtitles that are a few seconds out?

Use the fixed shift method and enter how far off they are, using a negative value if the subtitles appear too late. Every timestamp moves by that same amount.

My subtitles start fine but drift further out — what do I do?

That is a speed mismatch, not an offset, so a fixed shift will not fix it. Use the two-point fit: give a correct time near the start and another near the end and the drift is corrected across the whole file.

When should I use frame-rate rescaling?

When you know the subtitles were made for a copy running at a different frame rate, such as a 25 fps PAL release versus a 23.976 fps version. The tool scales every timestamp by the ratio between the two.

What does the speed factor mean?

It is how much every timestamp is multiplied by. A factor of exactly 1 means a pure shift with no stretching, while 1.042 means the subtitles are being slowed by about four percent.

What happens if a shift makes a timestamp negative?

It is clamped to 00:00:00,000 and counted in the results, since subtitle formats cannot express a time before the start of the media. A large clamped count usually means the shift is too big.

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