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SRT Validator
SRT/Subtitle Validator
Check your subtitle files for errors, timing issues, and formatting problems.
Check subtitle structure before upload
Best for
Video editors, captioners, educators, and translators reviewing an existing SRT or WebVTT file before delivery.
What it does
Paste subtitle text or open an SRT/VTT file, then inspect reported timestamp, cue-order, overlap, empty-text, duration, and line-length issues.
Before you rely on it
The check runs in the browser, but it is structural only. It does not correct the file, assess spelling or translation quality, preview playback, or guarantee platform acceptance.
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Upload or Paste Subtitles
Sample SRT
Sample VTT
Supports SRT and VTT formats
Upload File
Validate Subtitles
How to Use the Free SRT & VTT Validator
Paste subtitle text or open an .srt or .vtt file. The page reads the text and runs the structural checks when you select "Validate Subtitles."
1
Upload or Paste Your Content
Choose an SRT or WebVTT file from your computer, or paste the raw subtitle text into the editor. WebVTT files must begin with a WEBVTT header; optional header text and metadata before the first blank line are supported.
2
Analyze and Validate
Click "Validate Subtitles" to check cue structure, timestamp syntax, start and end order, overlaps, empty cue text, long lines, and unusually short or long cues.
3
Review Errors and Warnings
We provide a clear report of any issues found. Errors must be fixed for the file to be considered valid, while warnings offer suggestions for improving the readability and viewer experience.
What the Subtitle Check Covers
SRT and WebVTT timestamps
SRT timestamps must use commas. WebVTT timestamps use periods and may use MM:SS.mmm or HH:MM:SS.mmm; optional cue identifiers and settings after the end timestamp are supported.
Timing order and overlaps
Subtitle cues that are too long or overlap with each other can be jarring for viewers. By catching these timing issues early, you ensure that your audience can follow your content without distraction.
Cue structure and text
SRT cues need a numeric index, a timing line, and subtitle text. Missing indexes, timing arrows, and empty cue text are reported as errors.
Catch Readability Issues
We check for line lengths that exceed recommended limits (usually around 80 characters). This ensures that your text remains readable on mobile devices where screen real estate is at a premium.
Validator Scope and Limitations
This is a structural checker, not a subtitle player or converter. It does not rewrite files, check spelling, judge translation quality, or guarantee acceptance by every publishing platform. Advanced WebVTT blocks such as STYLE, REGION, and NOTE are skipped rather than analyzed. Use each platform's preview before publishing.
Who Relies on the Libraryminds SRT Validator?
Reliable subtitle structure matters across many industries. This tool gives professionals a focused technical check before previewing and publishing their video content.
Independent Filmmakers: To ensure that their festival submissions and streaming deliveries meet technical specifications.
E-Learning Creators: For checking the accuracy of lecture captions to provide a better learning environment for students.
Translation Agencies: To verify the formatting of translated files across multiple languages before delivery to clients.
Social Media Managers: To check auto-generated SRT files for errors before uploading them to platforms like LinkedIn or YouTube.
Frequently Asked Questions
What is the difference between SRT and VTT?
SRT (SubRip) is the most widely compatible subtitle format. VTT (WebVTT) is a newer format designed for HTML5 video players, offering additional features like text styling and positioning.
Does this tool fix my files automatically?
The validator identifies errors and tells you exactly where they are. While it doesn't automatically rewrite your file, it gives you the specific information you need to make corrections manually.
Is my subtitle data stored or shared?
The page reads the selected file into the editor and checks its text when you validate. Avoid pasting sensitive subtitle content into any web tool unless your policies allow it.
Why am I getting a "timing overlap" warning?
This happens when one subtitle cue is scheduled to end after the next one begins. This can cause flickering or missing text in many video players.
Can I validate subtitles in languages other than English?
Yes! As long as the file follows the standard SRT or VTT structure, our validator can check it regardless of the language of the text content.
What does the "line length" warning mean?
It means a single line of text exceeds 80 characters. We recommend keeping lines shorter to ensure they display correctly on all screen sizes, especially mobile phones.
How do I get auto-generated subtitles?
If you don't have a subtitle file yet, use Libraryminds to transcribe a video and export a timestamped SRT or VTT file.
Is there a limit to how many files I can validate?
The validator can be used without creating an account. If a request is blocked or the page is unavailable, try again later.
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