Merge subtitles online

Merging subtitle files

Merging joins two or more subtitle files into one continuous track and renumbers every cue sequentially so the result is a single, valid file. The classic reason is a movie released in two parts, the old CD1 / CD2 split, where each half of the film has its own .srt. Add the parts in order and the tool stitches them together end to end.

Getting the offset right

Each file in the merge list has its own offset in seconds. This matters because the second file's timestamps usually start again from near zero. Its first line might be at 00:00:30, even though in the combined video that moment is an hour in. Give the later part an offset equal to the point in the full video where it begins (for a 1-hour-2-minute first half, that's an offset of 3720 seconds) so its cues land in the right place instead of overlapping the first part. If the parts already use absolute timestamps for the whole film, leave the offset at zero.

Combining two languages

Merging is also how people build a dual-language subtitle for language learning, with one file in the language they are studying and one in their own. Because both tracks share the same timeline, set both offsets to zero and merge. Players show overlapping cues together, so each line shows with its translation. If the two language files were timed for different releases, sync one of them first. If you still need to produce the second language, see the guide on how to translate subtitles.

Splitting a subtitle file

Splitting does the opposite. It cuts one file into two, which is handy when a single subtitle covers a movie you have divided into two video files, or when you want only the first half of a track. There are two ways to split.

• By timestamp. Every cue that starts before the second you choose goes to part 1; the rest go to part 2. Use this when you know the exact moment the video was cut.
• By cue number. Part 1 gets cues up to the number you pick, part 2 gets the rest. Use this when you want to split on a specific line rather than a time.

Both parts keep their original timestamps, so part 2 will still be timed for its position in the full film. If you then play it against a video file that starts at zero, follow up by shifting part 2's timing back so it starts from the beginning.

Formats and file order

Merge and split work on SRT, VTT and ASS files, and the merged file is saved in the format of the first file you added. Order matters when merging. The files are joined in the sequence shown in the list, so add CD1 before CD2. You can remove a file or adjust its offset at any time and the preview updates instantly.

Is anything uploaded?

No. All joining and splitting happens in your browser using JavaScript. Your files are never sent to a server, there is no sign-up, and there is no limit on file size beyond what your device can hold in memory.