The short answer
Use the subtitle format your destination requires. SRT is a common text-and-timing deliverable for editors and hosting platforms. WebVTT is the format used by the HTML track element for web video. Both can carry caption text and timing; neither contains the video or creates a translated voice. Converting formats does not automatically preserve styling or translate the words.
The practical differences between SRT and VTT
SRT means SubRip Subtitle; VTT files use the WebVTT format. They are readable text files, but their syntax and supported features differ. Choose for the destination rather than assuming the newer-looking extension must produce a better result.
| Detail | SRT | WebVTT |
|---|---|---|
| Filename extension | .srt | .vtt |
| Opening header | No WEBVTT header | Starts with WEBVTT |
| Basic timestamp | 00:00:01,000 --> 00:00:03,000 | 00:00:01.000 --> 00:00:03.000 |
| Cue identifier | Conventionally a numbered sequence | Optional identifier |
| Formatting and placement | Basic formatting support varies by application | Cue settings and styling features, subject to player support |
| HTML video text track | Convert for a native HTML track workflow | Used by the HTML track element |
The same two captions in both formats
These original sample files describe an illustrative travel-mug demo; they are not a customer video or translation result. The first caption runs from one to three seconds, and the second from 3.5 to five seconds. The text and timing are the same in both files.
Notice the WEBVTT header, the blank lines between cues, and the comma-versus-period difference before milliseconds. Changing the filename extension alone does not update the content into the other format.
1
00:00:01,000 --> 00:00:03,000
Meet the travel mug.
2
00:00:03,500 --> 00:00:05,000
Keep the lid closed.
WEBVTT
1
00:00:01.000 --> 00:00:03.000
Meet the travel mug.
2
00:00:03.500 --> 00:00:05.000
Keep the lid closed.
Which format should you use?
For a hosting platform or video editor, start with its accepted-format list. If it requests SRT and you have simple timed captions, provide SRT. Do not convert an already accepted file merely to chase a supposed quality or SEO advantage.
For a native HTML video text track, use WebVTT. The track element connects the subtitle file to the media and identifies its language. An uploaded VTT file is not automatically connected to every video on a page; the player still needs the correct track configuration.
YouTube lists both formats, with different feature limitations: its basic SRT support ignores style markup, while its WebVTT support has limited styling. A feature existing in a file specification does not mean every destination implements it. Verify in the actual player.
What can change during conversion?
Simple caption text and timing are the easiest things to compare. Advanced WebVTT positioning, regions, style rules and metadata do not have a reliable one-to-one representation in a basic SRT export. Keep the original if those features matter to your video.
Recast’s converter validates timestamps and rejects malformed input instead of silently dropping invalid timed cues. In cross-format conversion, it writes sequential cue numbers and leaves out WebVTT NOTE, STYLE and REGION blocks. This is a basic subtitle conversion workflow, not a promise to preserve every feature of either format.
Converting to TXT removes timing. Converting TXT back creates a three-second placeholder cue for each non-empty line; it does not recover the original timing or listen to the video. Keep the timed source file if you may need it again.
Short VTT timestamps are not broken SRT timestamps
WebVTT can use a minutes-and-seconds timestamp such as 00:01.000. Recast accepts that short form as well as hour-based WebVTT timestamps. The following single cue should become a one-to-two-second SRT cue—not disappear or turn into a text-only file.
If conversion fails, check the source format, the WEBVTT header, and the timestamp syntax. Keep milliseconds to three digits; minutes and seconds must be in range. In a useful cue, the end must come after the start. Fix the file and inspect the full output rather than ignoring an error.
WEBVTT
00:01.000 --> 00:02.000
Close the lid.
1
00:00:01,000 --> 00:00:02,000
Close the lid.
A quick check before using a converted file
Select the original file in the converter, choose the required output format and inspect the preview. The preview may show only the beginning, so download and review the full result before attaching it to a video. Your selected subtitle contents are converted locally in your browser; no account is needed for this free tool.
- Compare the first cue, one cue in the middle, and the last cue against the original.
- Look for missing lines, altered accented characters, and timestamps that changed unexpectedly.
- Check important product names and numbers, even when the conversion is only a format change.
- Load the file with the intended video and test seeking, line breaks, positioning and readability.
- Retain the original file and document any style or metadata that was intentionally removed.
Does either format create a video or translate it?
No. A subtitle file does not contain video frames or a voice track. To produce an MP4 with permanent captions, supply the source video and the subtitle file to a tool that burns text into the picture. Those captions cannot be switched off in the exported video.
Changing SRT to VTT also leaves the language unchanged. Translation, transcription and dubbing are separate operations. If you need a localized product video rather than a different file extension, review the supported Studio workflow and check the result before publishing.