--- title: "Subtitle Merger" description: "Join multiple SRT or VTT subtitle files into one track. Append lays sequential parts end to end and fixes the timestamps that restarted at zero; Dual stacks two languages on one timeline. Nothing is uploaded." url: https://findutils.com/media/subtitle-merger/ category: media --- # Subtitle Merger Join multiple SRT or VTT subtitle files into one track. Append lays sequential parts end to end and fixes the timestamps that restarted at zero; Dual stacks two languages on one timeline. Nothing is uploaded. **Use this tool:** [Subtitle Merger](https://findutils.com/media/subtitle-merger/) ## Programmatic access - Browser-only: this tool works on a file, the DOM, or a browser API and has no REST or MCP id. ## Why merge subtitle files? A long recording is often captioned in pieces — a lecture split across three exports, a film released as two discs, a conference talk cut at the break. Each piece is numbered from 1 and timed from 00:00:00, so simply pasting them together gives you a file whose second half plays during the first. Merging fixes both: the timestamps are moved onto one continuous timeline and the cues are renumbered in order. The same page also stacks two languages on one timing, which is how a bilingual subtitle track is made. ## Frequently asked questions ### Do my subtitle files get uploaded? No. The files are read in your browser with the File API and the merge runs in the tab. Nothing is sent to a server, and you can confirm that by watching your browser's network tab while you merge. ### What is the difference between Append and Dual? Append is for parts of one recording: the files are laid end to end on a single timeline and the cues renumbered, so part two plays after part one. Dual is for two languages of the same recording: one file's timing is kept and the other's lines are added to the cues they overlap, so both appear on screen together. ### My second file starts at 00:00:00 again. Will that work? Yes, and that is exactly the case Append is built for. Each later file is moved so its first cue begins where the merged track has reached, plus any gap you set. Its own starting time does not matter. ### What if my parts already share one continuous timeline? Turn on Keep original times. Append would otherwise move them a second time and leave a long silence. With it on, every timestamp stays exactly as written and the cues are simply ordered by start time. ### Can I mix SRT and VTT files in one merge? Yes. Each file is parsed in its own format, and the output is written in one — by default whichever format the first file used, or the one you pick. ### How many files can I merge at once? Up to 20 in a single merge. Beyond that it is worth merging in batches, both for speed and because a list that long is hard to keep in the right order. ### What happens to the cue numbers? SubRip requires its cue numbers to be sequential, so the merged file is always renumbered from 1 regardless of what the inputs used. WebVTT identifiers are optional; the merged file fills them in the same order. ### One of my files has a broken timestamp. Does the merge fail? No. That file is listed with the line number of the bad timestamp and left out, and the remaining files still merge as long as at least two of them could be read. ### Does it change my subtitle text? No. Cue text, line breaks and WebVTT cue settings are copied exactly as read. Only timestamps and cue numbers change, and only in the way the mode you chose requires. ### Can it burn subtitles into a video? No. This tool works on caption files only. Burning text into the picture re-encodes the video, which is a different job with a very different cost. ### Why do some lines from my second language not appear in Dual mode? Dual attaches a secondary cue to the primary cue it overlaps in time. If a line in the secondary file covers a moment the primary file has no cue for, there is nothing to attach it to. Swapping which file is primary usually fixes it. ## Related Tools - [Subtitle Shifter](https://findutils.com/media/subtitle-shifter/) - [Subtitle FPS Converter](https://findutils.com/media/subtitle-fps-converter/) - [SRT to VTT](https://findutils.com/convert/srt-to-vtt/) - [ASS to SRT](https://findutils.com/convert/ass-to-srt/) - [SBV to SRT](https://findutils.com/convert/sbv-to-srt/) - [Subtitle Extractor](https://findutils.com/media/subtitle-extractor/)