YouTube Subtitle Checker

The YouTube Subtitle Checker takes whatever you paste into the SRT or SBV Content box, works out which of the two formats it is, converts it to the other and reports how many cues it found. Paste SRT and you get a cue count plus a YouTube-ready SBV block; paste SBV and you get a parse confirmation plus the equivalent SRT, downloadable with a .sbv extension.

SBV is the plain caption format YouTube has used since its early days, and files pulled from the YouTube caption editor still come back in it, while almost every subtitle editor and transcription service outputs SRT. Creators, channel managers and localisation freelancers end up bouncing between the two formats, usually just as an upload is due, so a quick srt to sbv converter that also sanity-checks the file removes real friction.

The differences are small but unforgiving. SRT numbers each cue, uses HH:MM:SS,mmm with a comma before the milliseconds and an arrow between times. SBV drops cue numbers, writes times as H:MM:SS.mmm with a dot and no zero-padded hour, and joins the pair with a single comma. The checker parses your input into timed cues first, so text that yields zero cues in both parsers is reported as unrecognisable rather than silently converted into garbage.

Everything runs in your browser, so captions containing unpublished scripts are never uploaded.

• Automatic format detection: The tool tries to read the SRT or SBV Content box as SRT first and falls back to an SBV parser, so you never have to tell it which format you pasted.
• Two-way conversion: SRT input is converted to YouTube's SBV layout, and SBV input is converted back to numbered SRT, which covers both directions of the usual workflow.
• Cue count validation: Every run reports how many cues were parsed, giving you an immediate sanity check that the file is complete rather than truncated halfway through.
• Clear failure message: If neither parser finds cues, the tool says the content is not recognisable instead of returning an empty or corrupted result you might upload by mistake.
• Correct timestamp rewriting: Conversion handles the comma-to-dot millisecond separator and the presence or absence of cue numbers, which are the two things people get wrong when editing by hand.
• Download as .sbv: The converted output can be saved directly with the .sbv extension YouTube expects, so there is no renaming step before upload.
• Browser-only processing: No caption text is transmitted anywhere, so scripts under embargo stay on your machine.

1. Paste your captions into the SRT or SBV Content box, or press Load sample to see the expected shape of an input file.
2. Press Run; the checker decides for itself whether the text is SRT or SBV, so no format selector is needed.
3. Read the first line of the result, which states the format detected and how many cues were parsed, and compare that count with what you expect from your script.
4. Scroll through the converted block underneath and spot-check the first and last timestamps against your source.
5. If you see the "no recognizable content" message, check your input for missing blank lines between cues or malformed timestamps and paste it again.
6. Download the result as a .sbv file, or copy it if you are pasting straight into another editor.
7. Upload the .sbv in YouTube Studio under the video's subtitles tab and preview a few cues in the player before publishing.

Example 1 - SRT to SBV for a YouTube upload. The cue numbers disappear, the comma before the milliseconds becomes a dot, and the two times are joined by a comma.

Input (SRT):
1
00:00:01,000 --> 00:00:04,000
Welcome back to the channel.

Output (SBV):
0:00:01.000,0:00:04.000
Welcome back to the channel.

Example 2 - SBV back to SRT for editing. A file downloaded from YouTube Studio is SBV, but your subtitle editor wants SRT, so the checker adds cue numbers and restores the arrow separator.

Input (SBV):
0:01:12.500,0:01:15.250
Let's look at the numbers.

Output (SRT):
1
00:01:12,500 --> 00:01:15,250
Let's look at the numbers.

Both conversions keep the millisecond values intact, so sync is preserved exactly and nothing needs retiming afterwards.

• Uploads that are accepted first time: Getting the SBV timestamp punctuation right means YouTube ingests the file instead of returning a vague parse error minutes before a scheduled premiere.
• No manual find-and-replace: Converting by hand across hundreds of cues invites a missed comma that breaks everything; automated conversion removes that whole class of mistake.
• Confidence that the file is complete: The cue count gives you a number to check against your script, catching truncated exports before they reach the audience.
• Works in both directions: Whether you are handing captions to a translator in SRT or pushing them back to YouTube in SBV, one page covers the round trip.
• Better accessibility on your channel: Accurate captions that actually upload mean deaf and hard-of-hearing viewers, and anyone watching muted, get the full content.
• Unreleased content stays private: Because conversion happens in the browser, caption text from an unpublished video is never sent to a server.