Create · Converter · Phase 2

Subtitle time shifter

Move every subtitle cue forward or backward while preventing negative timestamps. Change the inputs, review the method, and use the output as a transparent starting point.

How Free Creator Toolkit estimates results
Your inputs

Shift every cue together

Inputs stay in this browser. Saving a scenario is optional and local to this device.

Paste subtitles or load a local file.

No file selected

Use a negative value to move cues earlier.

seconds
Converted result

Shifted subtitles

1
00:00:02,500 --> 00:00:05,500
Welcome to this creator workflow.

2
00:00:06,500 --> 00:00:10,000
Today we will turn an idea into a clear plan.

2 cues shifted by 1.5 seconds.

Review sources and method

Share links include only numbers and choices. Local saves remain in this browser until you delete them; file and long-text content is excluded.

Saved on this device0 of 6 saved

Save a fresh result to compare or reuse it later on this device.

Formula or method

Shift every parsed cue timestamp by the supplied millisecond offset

Assumptions

  • Negative timestamps are clamped to zero.
  • Review the first and last cue after shifting.

Sources and verification

Use the result well

How to use the subtitle time shift

Move every recognized subtitle cue earlier or later by one signed offset while preserving cue duration. This is useful for a consistent sync error; it is not a replacement for retiming captions that drift progressively across a video.

Measure one consistent offset before shifting

Find a clear spoken word or sound near the beginning and compare its video time with the caption start. If captions appear 1.5 seconds late throughout the program, enter -1.5 seconds to move them earlier. Test another cue near the end before applying the result to the whole file.

The tool prevents negative timestamps by clamping them to zero. When an early cue crosses zero, its duration can change, so inspect the beginning carefully and rewrite or remove unusable cues rather than assuming every shifted range remains ideal.

Distinguish an offset from frame-rate drift

If captions start in sync and become increasingly late or early, one fixed shift will not solve the problem. Check edit changes, frame-rate interpretation, time-stretching, dropped sections, and whether the subtitle file belongs to a different master.

Processing stays in the browser and the original file is not changed. Download a new copy, review beginning, middle, and end in the destination player, and keep the original until delivery is approved.

Common questions

Questions about this tool

Should I use a positive or negative offset?

Use a negative offset when captions appear late and need to move earlier. Use a positive offset when captions appear before the matching audio.

What happens to timestamps that move below zero?

They are clamped to zero. Review those cues because clamping can shorten them or create overlaps at the start.

Can this fix captions that drift over time?

No. Progressive drift usually needs time scaling, frame-rate correction, or manual retiming rather than one fixed offset.