Convert .sub subtitle files to SRT
The .sub extension is used by three unrelated formats. Two are text, MicroDVD and SubViewer, and convert to SRT here. The third, VobSub, is a set of pictures from a DVD and cannot be converted without character recognition. Upload your .sub file, choose the frame rate if it is MicroDVD, and download SRT with every line timed. Jobs with up to 3,000 lines are free in full; bigger batches are $5, paid once.
- MicroDVD ({100}{250}Text) and SubViewer 2 (00:01:02.50,00:01:04.00) recognized from the content
- MicroDVD frame rate taken from the file's first line when it states one
- Otherwise the rate you choose: 23.976 by default, 24, 25, 29.97, 30, 50, 59.94 or 60
- | and [br] line breaks and MicroDVD italics kept
- VobSub .sub/.idx and Blu-ray .sup refused: they are images
Which .sub do you have?
Open the file in a text editor. If lines look like {1200}{1290}Where are you going?|Home., it is MicroDVD: the numbers in braces are frame numbers, and | separates two lines. If you see times such as 00:01:02.50,00:01:04.00 followed by text, with [br] for line breaks, it is SubViewer 2. If the editor shows unreadable symbols and there is an .idx file of the same name next to it, it is VobSub, which stores each subtitle as a small image.
The converter tells MicroDVD and SubViewer apart by their content, so you do not have to choose. A VobSub file is recognized as image-based and skipped, rather than turned into a file full of garbage.
Getting the frame rate right
MicroDVD counts frames, so the time of each line depends on the frame rate. Frame 2400 is 1 minute 40 seconds at 24 fps but 1 minute 36 seconds at 25 fps. Many MicroDVD files begin with a line such as {1}{1}23.976 that states the rate, and then that value is used. If there is no such line, the rate you pick is used, 23.976 by default, which suits most films.
A wrong rate shows as subtitles that start nearly right and drift further off as the film goes on. If that happens, convert again with 25, the usual rate for European TV and DVD releases, or 24. SubViewer files store real times, so the frame rate does not affect them.
Why VobSub cannot be converted here
A VobSub .sub file holds bitmap pictures of the subtitles, ripped from a DVD, and the .idx file says when each picture appears. There is no text to convert. Turning those pictures into text takes optical character recognition, and this tool does not do that. The same goes for Blu-ray .sup files. Once you have an SRT from such a source, this site can convert, re-time or translate it.
How the tool works, what it costs and how your files are handled is on the Subtitle Converter page; prices for every tool are on the pricing page.
Last updated
Questions and answers
Can ChatGPT convert a MicroDVD .sub file to SRT?
On a few lines it can, if you tell it the frame rate. A whole film means dividing frame numbers for well over a thousand lines and retyping each time, which chat replies tend to cut short or get wrong in places. The converter does the arithmetic for every line.
Which frame rate should I choose?
The rate of the video the subtitles were made for. Start with 23.976; if the subtitles drift later in the film, try 25 or 24. A rate stated in the file's first line is used automatically.
Why does my .sub file come out empty or get refused?
It is probably VobSub, the image-based DVD format that comes with an .idx file. It contains pictures, not text, and cannot be converted without character recognition.
What does it cost?
Free in full for jobs with up to 3,000 lines in total. Larger jobs, up to 50 files or a ZIP and 50,000 lines, are $5, paid once.
Can I convert SRT back to MicroDVD?
Yes. Download MicroDVD SUB; the file starts with a frame rate line using the rate you chose, and italic lines are marked with {y:i}.
Are old Cyrillic or Arabic .sub files supported?
Yes. Windows-1251, Windows-1256, Greek, Hebrew and Western encodings are recognized, and the SRT is saved as UTF-8.