Merge two SRT files into one subtitle with both languages
Have the same film in two subtitle files, one per language? Upload both and get a single file that shows the two languages at once, paired line by line by their timings. No AI model is involved and nothing is translated. Joining is free in full up to 3,000 lines; longer files are $5. This page starts with the first language at the top of the screen and the second at the bottom.
- Exactly two files: the first is the main language, the second is added to it
- Each second-file line joins the first-file line it overlaps most in time
- Second-file lines that overlap nothing keep their own timing
- Accepts .srt, .vtt, .ass and .ssa; downloads SRT, VTT or ASS
- Free up to 3,000 lines; up to 10,000 lines for $5
How the lines are paired
Two subtitle files for the same film rarely break the dialogue in the same places. One may show a sentence as a single subtitle where the other splits it in two, and their start and end times differ by a fraction of a second. So the files are not matched by line number. For every line of the second file, the tool looks at the lines of the first file it overlaps in time and attaches it to the one with the most overlap. Two short lines that both fall inside one longer line are both shown with it.
A line of the second file that overlaps nothing in the first, such as a sign translated in only one file, is not dropped: it keeps its own timing and appears on its own, in the second language only. A line of the first file with no partner simply shows alone. The result is one file in time order, named after the first file, for example Movie.dual.srt.
When the files come from different releases
Pairing by time only works when both files are timed for the same video. A file made for a different release may run a second or two early or late, drift further as the film goes on, or follow a different frame rate, such as 25 instead of 23.976. Merged as they are, lines would pair with their neighbors. Fix the timing of one file first with the subtitle sync tool at /en/fix-subtitle-sync, which shifts, stretches or converts the frame rate of a whole file, then merge the two.
Layouts and formats
- Split: first language at the top of the screen, second at the bottom ({\an8} in SRT, line:0 in VTT, a Top style in ASS)
- Stacked: both at the bottom, first language on the upper line
- An .ass or .ssa input is read as text; italics and a position code are kept, its styling is not
- Downloads are UTF-8 with a byte order mark, so Arabic, Persian and Chinese display correctly
How the tool works, what it costs and how your files are handled is on the Dual Language Subtitles page; prices for every tool are on the pricing page.
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Questions and answers
Can ChatGPT merge two SRT files?
For a few dozen lines it can line them up. For a whole film, the reply tends to stop partway, and because it pairs lines by reading rather than by their times, it can match the wrong lines or alter time codes.
Is it free?
Yes, in full, when the merged file has up to 3,000 lines, downloads included. Longer files show the first part free, and the whole file, up to 10,000 lines, is $5 paid once.
Which file becomes the top language?
The first of the two files. It goes to the top of the screen in split layout and on the upper line in stacked layout.
What if the lines do not match up?
The two files are probably timed for different releases. Fix one with the subtitle sync tool so both match the same video, then merge again.
Can I merge more than two files?
No. Each job joins exactly two files.
What if I only have one language?
Choose "Translate my file" instead: one file is translated into the second language and both are shown together.