Convert Subtitles Between SRT, VTT & ASS Online

How it works

Subtitle format comparison

Not sure which format you need? The table below shows what each one supports and where it is used. Most players want SRT; web video (HTML5 <video>) wants VTT; anime and styled subtitles use ASS.

Popular conversions

Jump straight to a dedicated, single-purpose converter for the most common pairs. Each runs locally in your browser with the same privacy guarantee.

Frequently asked questions

Which subtitle format should I use?

Choose the format based on where the subtitles will be played, not on whichever one you happen to have. Use SRT for anything played in a media player, TV, phone or editing application — it is the safest common denominator and opens everywhere. Use VTT (WebVTT) when the video lives on a web page, because browsers only render .vtt through the HTML5 <track> element. Use ASS when the visual presentation matters: anime fansubs, karaoke, styled dialogue, or subtitles that must sit next to on-screen text. Use SBV only if you are working with an older YouTube export, and convert it to SRT as soon as you can. Use TXT when you want a readable transcript rather than subtitles at all.

If you are unsure, keep two copies: an SRT master for compatibility and a VTT copy for the web. Both can be produced from the same source file here in seconds.

Understanding subtitle encodings: why text looks garbled

Subtitle files are just text, and text has to be stored using a specific character encoding. Modern tools write UTF-8, which handles every language. Older Windows tools — and a large share of Chinese subtitle sites — write GBK or GB18030 instead. When a player assumes UTF-8 but the file is actually GBK, every non-ASCII character renders as nonsense, and readable Chinese turns into sequences of meaningless symbols. The same thing happens with Japanese Shift-JIS files and with Western files saved as Windows-1252.

The fix is to detect the real encoding and convert the text to Unicode before doing anything else, which is exactly what this tool does automatically when you drop a file. The detected encoding is shown next to the file name so you can confirm it. If a file still looks wrong afterwards, open the original in a text editor, re-save it as UTF-8, and convert again.

Troubleshooting common subtitle problems

The subtitles are consistently early or late

Enter a value in the Time shift field before converting — negative to show cues earlier, positive to delay them. A fixed offset corrects a constant error cleanly.

The subtitles drift further out of sync as the video plays

That is a frame-rate mismatch, for example subtitles timed for 25 fps played against a 23.976 fps video. A constant shift cannot fix it; you need a frame-rate conversion or a two-point re-sync in a subtitle editor.

Characters look like garbage

An encoding problem. This tool detects UTF-8, GBK/GB18030 and Windows-1252 automatically. If the source uses something rarer, re-save it as UTF-8 first and convert again.

No cues were found in my file

The file may be empty, or it may use an image-based format such as idx/sub or VobSub, which store pictures of text rather than characters. Those cannot be converted to SRT without optical character recognition.

How to add subtitles to a video

Once you have the right format, adding subtitles is usually just a matter of file placement. Put the subtitle in the same folder as the video and give it the same base name — movie.srt beside movie.mp4 — and most players, including VLC and Total Video Player Pro for Mac, load it automatically. For web video, add a <track> element pointing at your .vtt file inside the <video> tag. To make subtitles permanent, burn them in using HandBrake's Subtitles tab or FFmpeg with ffmpeg -i movie.mp4 -vf subtitles=movie.srt out.mp4. Some containers, notably MKV and MP4, can also store subtitle tracks inside the video file itself, which removes the need for a separate file entirely.

Working with several subtitle files

Convert one file at a time: drop it, convert, download, then reset and drop the next. Because nothing is uploaded there is no queue and no waiting between files, so working through a folder of subtitles takes only a little longer than converting a single one. If you need the same timing correction across a set of files, enter the same Time shift value before each conversion so the whole set stays consistent. Keep your originals until you have confirmed the converted files play correctly — particularly with ASS sources, where styling cannot be recovered once it has been stripped.