Subtitle converter
Convert subtitle files between SRT, VTT, ASS and every common format
Upload a subtitle file, several files or a ZIP, and download it as SRT, VTT, ASS, SBV, TTML, MicroDVD SUB or plain text. Every line keeps its start and end time, and no AI model rewrites anything: the conversion is done by code that follows each format's rules. Jobs with up to 3,000 lines in total are free in full, downloads included; bigger batches, up to 50 files or a ZIP, are $5 paid once. A chatbot can turn a few SRT lines into VTT, but on a full movie it has to retype every time code, and long files tend to come back cut short or with times changed.
- Reads SRT, VTT, ASS, SSA, SBV, TTML, DFXP, SUB (MicroDVD and SubViewer) and SAMI
- Download SRT, VTT, ASS, SBV, TTML, MicroDVD SUB or plain text from one upload
- Times kept to the millisecond, lines never merged or split
- Free in full up to 3,000 lines, no account needed
- A season or a ZIP of files converted as one job for $5
- Old Arabic, Persian, Cyrillic, Greek and Hebrew encodings read and saved as UTF-8
What you get back
One converted file for each file you upload, under the same name with the new extension, for example movie.vtt. Several files download together as one ZIP. Before you download, the lines are shown on screen in SRT layout, and you can correct any of them; the download uses your edits.
- Every subtitle line with its original start and end time. ASS stores hundredths of a second and MicroDVD stores frames, so those two formats round to their nearest step.
- Italic, bold and underline carried between formats that support them. The {\an8} code for top-of-screen lines moves between SRT and ASS, and becomes line:0 in VTT.
- From ASS or SSA: positioning, karaoke, fades and other effects cannot exist in SRT or VTT, so they are removed there, and drawing lines are left out. Converting to ASS creates a file with one Default style.
- SRT, VTT, ASS, SBV and SUB saved as UTF-8 with a byte order mark, and SRT with Windows line endings, which older TVs and players read most reliably.
- Every format button works on the same upload, so you can take SRT for the TV and VTT for a web player without uploading again.
Converting subtitles with a chatbot, and with this tool
ChatGPT, Claude and Gemini know the subtitle formats, and for a short snippet they convert it correctly. A real subtitle file is long and full of numbers, and the risk grows with every line that has to be retyped.
| Your situation | A chatbot | This tool |
|---|---|---|
| A few lines of SRT to turn into VTT | Usually gets it right | Gets it right too, and gives you a file to download |
| A full-length movie | Has to retype every time code; long replies tend to stop partway | Converts the whole file in one pass, up to 50,000 lines per job |
| An ASS file with styling, to SRT | May leave override tags in the text or skip lines | Turns italic, bold and {\an8} into SRT tags and removes the rest |
| Streaming-style DFXP with tick times | Has to do arithmetic on values such as 15015000t for every line | Reads tick, frame and clock times and writes standard time codes |
| A season of episodes in a ZIP | One file per chat, pasted by hand | Upload the ZIP; every file converts and comes back in one ZIP |
| An old Windows-1256 or Windows-1251 file | The text is often already garbled by the time it is pasted | Detects the encoding from the bytes and saves UTF-8 |
How to convert a subtitle file
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1
Upload your files
Drop in one subtitle file, several, or a ZIP. The format is recognized from the content, so a file with the wrong extension still reads. For frame-based MicroDVD .sub files, pick the frame rate of your video.
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2
Check the lines on screen
The converted lines appear in SRT layout with their time codes. Correct any text in place. Jobs up to 3,000 lines are free in full; for bigger jobs, the first block is shown free.
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3
Download in any format
Choose SRT, VTT, ASS, SBV, TTML, SUB or plain text. Bigger jobs unlock for $5, paid once, and every format button stays available for the whole job.
Why converting a long subtitle file trips up general AI assistants
Converting subtitles is mostly bookkeeping. SRT writes 00:01:02,500, VTT writes 00:01:02.500, ASS writes 0:01:02.50, SBV writes 0:01:02.500, MicroDVD counts frames, and TTML may count ticks of ten million per second. A chat assistant knows these rules, but to apply them it has to write the whole file back out by hand, one time code after another.
On a short clip that works. A feature film often runs to well over a thousand lines, and a single reply does not hold it. The assistant tends to stop partway, ask you to continue, or skip a stretch near the end. Arithmetic is the other weak point: turning frame numbers or ticks into time codes for every line is where small slips creep in, and one wrong time puts a line on screen at the wrong moment.
This converter does not generate text. It reads your file into separate lines with times in milliseconds, then writes each line in the format you pick, using fixed rules for every format. The same input always gives the same output.
What people convert
- ASS or SSA anime subtitles to SRT for a TV, a streaming box or a video editor
- SRT to VTT for an HTML5 video player or a course platform
- VTT downloads to SRT for VLC, Plex or Kodi
- YouTube SBV captions to SRT, or SRT to SBV
- TTML, DFXP and XML subtitles from streaming services to SRT
- Old MicroDVD and SubViewer .sub files, and Korean SAMI .smi files, to SRT
Details that matter
MicroDVD .sub files store frame numbers, not times. If the file's first line states its frame rate, that rate is used; otherwise the one you choose is, with 23.976 as the default. A wrong frame rate makes the subtitles drift further off as the film goes on, so if the result drifts, try 25 or 24. The same setting applies when you download MicroDVD.
SAMI files can hold several languages. The converter takes the first language class that contains text, for example KRCC in Korean files. VTT position settings and STYLE blocks have no SRT equivalent and are not carried into SRT; TTML keeps italic text but not colors or regions.
Files saved in an old Windows encoding are recognized and converted: Arabic and Persian (Windows-1256), Cyrillic (Windows-1251), Greek, Hebrew and Western. UTF-8 and UTF-16 files are read as they are.
What it does not do
It converts text subtitles only. Image-based subtitles, such as VobSub .sub/.idx pairs from DVDs and Blu-ray .sup files, are pictures of text and would need character recognition, which this tool does not do. Subtitles burned into the picture and video files are not supported either.
It does not re-time or translate. If the subtitles are out of sync with your video, use Fix Subtitle Sync after converting; to change the language, use the Subtitle Translator. Styling that a format cannot hold is removed rather than imitated, so an elaborate ASS sign or karaoke line becomes a plain line in SRT.
By language and situation
Convert ASS subtitles to SRT
ASS and SSA files are common for anime and styled fan subtitles, but many TVs, streaming boxes and video edito...
Read more →Convert VTT subtitles to SRT
WebVTT is the caption format of the web: browsers, online course platforms and many video sites use it. Plenty...
Read more →Convert SRT subtitles to VTT
Browsers play captions in WebVTT, not SRT, so a web page, a self-hosted player or a course platform often asks...
Read more →Convert YouTube SBV captions to SRT
SBV is YouTube's own plain caption format. It is what you get when you download captions from YouTube in that...
Read more →Convert DFXP or TTML subtitles to SRT
Streaming services and broadcasters deliver subtitles as XML: TTML, often saved as .dfxp, .ttml or .xml. Most...
Read more →Convert SUB subtitles to SRT
The .sub extension is used by three unrelated formats. Two are text, MicroDVD and SubViewer, and convert to SR...
Read more →What it costs
Short jobs, first part
Free
Jobs with up to 3,000 subtitle lines in total are free in full, downloads included; one movie is usually under that. Bigger jobs show the first block on screen. 1 job a day without an account, 3 with a free account.
Whole job
$5
One payment for every file in the job: up to 50 files or a ZIP, and 50,000 lines. Every download format included. No subscription.
Unlimited
$19 / week
Every tool on the site, with subtitle jobs of up to 200,000 lines.
Questions and answers
Can ChatGPT convert SRT to VTT or ASS to SRT?
For a short file, yes, and usually correctly. On a full movie or episode it has to retype every time code, so replies tend to stop partway, skip lines or change times. This converter applies each format's rules to every line in code, with no AI model involved.
Is it free?
Jobs with up to 3,000 subtitle lines in total are free in full, downloads included, with no account. Bigger jobs show the first block free on screen; the whole job, up to 50 files or a ZIP and 50,000 lines, is $5 paid once. Unlimited, at $19 a week, covers every tool on the site.
Which formats can it read and write?
It reads SRT, WebVTT, ASS, SSA, SBV, TTML, DFXP and XML, MicroDVD and SubViewer .sub, and SAMI .smi. It writes SRT, VTT, ASS, SBV, TTML, MicroDVD SUB and plain text, and you can download the same job in several of them.
Will italics and styling survive?
Italic, bold and underline carry over between formats that support them, and the {\an8} top-of-screen code moves between SRT and ASS (in VTT it becomes the line:0 setting). ASS positioning, karaoke, fades and drawings cannot exist in SRT or VTT and are removed there; colors and fonts from ASS styles are not carried.
Can it convert VobSub .sub and .idx or Blu-ray .sup files?
No. Those files contain pictures of the subtitles, not text, so they need character recognition. Text-based .sub files in MicroDVD or SubViewer format convert normally.
Which frame rate should I choose for a MicroDVD .sub file?
The frame rate of the video the subtitles were made for. Most films are 23.976 and European TV and DVD releases are often 25. If the file states its own frame rate on its first line, that rate is used automatically.
Can I convert a whole season at once?
Yes. Upload up to 50 files, or a ZIP with the season inside, and every file converts in one job. Hidden files and macOS __MACOSX folders in the ZIP are skipped, and the results download as one ZIP.
What happens to old Arabic, Persian or Russian files?
Files saved in Windows-1256, Windows-1251, Greek, Hebrew or Western Windows encodings are recognized from their bytes and saved as UTF-8. For Persian and Arabic files that are already garbled or have punctuation on the wrong side, use Fix Persian & Arabic Subtitles.
Are my files private?
Only you can open your job. No AI model is involved, so the subtitle text is not sent to any model provider. Jobs uploaded without an account are deleted after 7 days, and you can delete any job yourself at any time.
Updated October 25, 2026 · APPFACT STUDIO LTD