# Merge Two Subtitles Into Bilingual Captions

> Free bilingual subtitle merger: pair two SRT / VTT / ASS files by timing into one two-line subtitle, or split a bilingual file back into two. Runs in-browser.

- URL: https://qilingtools.com/en/video/subtitle-merge
- Category: Video Tools (https://qilingtools.com/en/video)
- Tags: [Video](https://qilingtools.com/en/tags/video), [Subtitles](https://qilingtools.com/en/tags/subtitle)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

You have a Chinese subtitle and an English one and want the two-line bilingual look. Doing it by hand takes all night, and the hard part is that the two files rarely break lines the same way: one English sentence is split across two cues while the Chinese stays on one. This tool pairs cues by how much their timings overlap, joins one-to-many matches into a single line, and tells you exactly how many cues it could not pair instead of dropping them quietly. It also runs the other way and splits a bilingual file back into two.

## How to use

1. Drop the primary subtitle on the left (it becomes the top line) and the secondary on the right
2. Keep “By timing” for files on the same timeline, or pick “By index” for a one-to-one pair
3. If the secondary runs early or late, type a time shift to pull it back
4. Check the preview and download; ASS output also lets you style each language

## Features

- Pairs by timing overlap, so different line breaks still match and one-to-many joins into a line
- “By index” mode pairs cue by cue, keeping the primary timings
- Counts what paired and what was left over on each side, and you choose whether leftovers stay
- ASS output writes one line per language with two styles — primary larger on top, secondary smaller below
- Split mode recovers two single-language files, detecting the CJK line automatically
- Reads and writes SRT / WebVTT / ASS·SSA / LRC / SBV, with GBK and Big5 mojibake re-decoded

## FAQ

### The two files are a few seconds apart — now what?

Use the time shift: negative if the secondary runs early, positive if it runs late; the preview updates as you type. For a large gap, or drift caused by a different frame rate, align one file with two-point sync in the subtitle editor first.

### What should the minimum overlap be?

It is the share of the shorter cue that must overlap. The default is 20%; raise it above 40% when the timings are tight to avoid wrong matches, and drop it to 10% when they wobble. Watch the primary-only count — the lower it is, the better the pairing.

### Why does my player show only one line?

Two lines in SRT are just a line break, and some players render them as one or crowd them together. For exact control over position and size, export ASS: it writes a separate line per language, each with its own style.

### Can it split a bilingual file?

Yes — switch to split mode. By default the line containing CJK characters is treated as the primary one, and you can also force the first or second line. With three or more lines, the first is primary and the rest go to the secondary file.

### Are my subtitles uploaded?

No. Reading, parsing, pairing and generating all happen in the browser; the page sends no content anywhere.

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