Merge Two Subtitle Files Into a Bilingual Subtitle
Learning a language? Watch with both subtitles at once. Drop two files, choose which language goes on top, and download one dual-language subtitle.
1 · First language (timing source)
2 · Second language
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How to use the Bilingual Subtitle Merger
- Drop the first-language file (its timing is the master) on the left and the second-language file on the right.
- Choose how lines are matched: Time overlap pairs cues that are on screen together (recommended). Line number only works when both files have exactly the same number of cues.
- Pick which language is on top, and how the lower line is styled: italic, colour or plain.
- Click Merge subtitles, review the preview and download as SRT, WebVTT or ASS.
How the pairing works
Two subtitle files for the same video rarely have the same number of cues because translators split sentences differently. Matching by time overlap solves this: for each cue in file 1 the tool collects the cues of file 2 that overlap it in time and puts their text underneath. Cues that find no partner can be kept from file 2 as separate cues so no translation is lost.
Make sure both files are in sync first
If the two files come from different releases they may be a few seconds apart. Check both with a video player before merging, and fix any offset with the timing shifter or two-point sync. A good test: the first and last lines of both files should appear at nearly the same time.
Styling the second line
- Italic works in every player and is the safest way to distinguish the two languages.
- Colour uses a
<font color>tag in SRT, which most players support but some TVs ignore. - ASS output lets you set bigger text for the main language and smaller text for the second; open the file in a text editor to adjust.
Good uses
Language learners often use a dual-language subtitle to see the foreign dialogue and a translation together. Teachers and translators use them for review, and fan communities share them as a convenience. Some video platforms (e.g. web players) show only a single subtitle track, which is exactly why a merged file helps.
Frequently asked questions
Which file should be first?
The one whose timing you trust most — usually the original-language subtitle, or the one that is better synchronised with the video.
What if the files have a different number of cues?
Use “Time overlap” matching. It does not need equal counts.
Can I put the translation on top?
Yes, change “Top line” to “File 2 on top”.
How do I get a different font size for each language?
Export as ASS and edit the styles in the file, or use SRT to ASS on each file before merging in an editor such as Aegisub.
Does the merged file work on TVs?
The SRT output with italic styling works on almost all of them. ASS and colour tags are best on computers.
Are the files uploaded?
No. Both are processed locally.