Merge SRT files and shift subtitle timing

A recording cut into parts gives one subtitle file per part, each starting at 00:00:00. Add them in order and get one file with every part at its real position. Add a single file to move all its captions earlier or later. Nothing is uploaded.

Add .srt or .vtt files, in order part 1 first; add more any time, reorder with the arrows

Where part 2 starts

Each part's subtitles count from zero, so part 2 has to move forward by exactly the length of part 1. The length of part 1 is the length of its audio, not the time of its last caption: if the speaker stopped 20 seconds before the cut, the last caption ends 20 seconds early. The tool's suggestion is the end of the previous part's last caption, rounded up to the next whole second. It is right when the cut fell mid-speech, which is most cuts.

When you know the cut points, use them. Recordings split by an app or a recorder are usually cut at fixed lengths (every 12, 15 or 30 minutes), so type that length in Parts were cut every and every start is set at once. Or type a start for each part by hand, as 12:00, 1:02:30 or a number of seconds.

Shift for out-of-sync captions

With one file, the tool only shifts. Watch for the first caption: if it appears 2.5 seconds before the words, type +2.5; if it appears after them, type a negative number. A fixed shift fixes a constant offset, the kind an intro or a trimmed opening causes. It does not fix drift, captions that start right and fall further behind, which comes from a different frame rate or a different edit of the video.

SymptomCauseFix
Every caption early or late by the same amountAn intro added or trimmedShift by that amount
Part 2 captions play over part 1Parts transcribed separately, each from 00:00Merge with the right start for each part
In sync at the start, later and later afterDifferent frame rate (25 against 23.976 fps)New subtitles timed from this video's audio
In sync, then suddenly off from one pointA scene cut or added in this editShift from that point, or new subtitles

Before merging, check each file for broken timing lines; after, translate the merged file or turn it into plain text. If the recording is still long enough to need cutting for some other service, the large recording calculator shows why it does not here.

Questions

How do I merge two SRT files into one?

Add both files in order. Each part after the first starts at 00:00:00 in its own file, so it has to be moved to where it begins in the full recording. The tool suggests that point from the end of the part before (rounded up to the next second); if you cut the recording at a known time, such as every 30 minutes, type it in. Then download one SRT or VTT.

How do I fix subtitles that are out of sync?

Add one file and type how far to move every caption: +2.5 if the captions show 2.5 seconds too early, -1.2 if they show 1.2 seconds too late. Captions moved before 00:00:00 are dropped.

Why are my subtitles out of sync in only part of the video?

A fixed offset cannot fix drift: subtitles that start in sync and slowly fall behind were timed for a different frame rate (25 against 23.976 frames per second, for example) or a different cut of the video. The cleanest fix is new subtitles timed from the audio of the video you actually have.

Are my files uploaded?

No. The files are read and joined by JavaScript in this browser tab. Nothing is sent to WhipScribe or anyone else.

More free subtitle tools

Check

SRT checker

Every error with its line number, and a repaired file in one click.

Text

SRT to TXT

Captions rejoined into readable paragraphs.

Audio

Split audio

Cut a part out of a long recording in your browser.

No transcript yet?

Start from the recording and download the subtitle file: see the SRT file generator, the YouTube to SRT page and the WebVTT generator.