SRT and VTT Subtitle Validator
Check SRT and WebVTT structure, timestamps, overlaps, empty cues, and readable line length before delivery.
Validate SRT and VTT
Validation report
The conversion runs in this page. Output claims are limited to the formats and browser capabilities shown here.
Frequently Asked Questions about Subtitle Conversion
Does validation guarantee platform acceptance?
No. The report checks common subtitle structure and timing problems; each video platform can apply additional rules.
Will my original file be changed?
The result is downloaded separately. Keep the original until you have checked the Validation report.
Does a passing report guarantee platform acceptance?
No. The report covers basic structure and timing checks. A platform can require additional metadata or impose different limits.
Can it compare subtitles with a video?
No. It reads the subtitle text only and cannot confirm whether each cue matches the spoken audio.
Will the validator repair the file?
No. It reports issues so you can correct the source and run the check again.
Can I rely on the result without checking it?
Review the preview and open the downloaded file in the tool that will use it. A conversion can be structurally successful while still needing a correction for layout, content, timing, color, or application-specific settings.
SRT and VTT Subtitle Validator
Subtitle validation is a practical preflight step before a caption file is delivered to a client, uploaded to a player, or attached to a video release. This page checks the basic structure of SRT and WebVTT text. It reads cue timing, detects malformed timestamp lines, notices empty cue text, reports overlapping cues, and flags long text lines. The report is a readable checklist for the file that was supplied. It is not a certification for every video platform because each platform can apply its own limits and caption rules.
This page is built for a clear input-to-output task. It gives the browser a file or text value, applies the conversion described above, and leaves the result available for review before download. A successful file download does not mean that every application will interpret the result in the same way. The safest workflow keeps the source file, checks a representative section, and tests the output in the application or player that will receive it.
How to use
Upload an SRT or VTT file, or paste its text into the editor. Click Convert to produce a validation report. Start with the format and cue count, then read each reported issue in order. Correct the source file in your caption editor and run the check again. If the report passes, still preview the captions with the target video because a structurally valid file can have poor reading speed, inaccurate wording, or a timing problem that requires knowledge of the video.
- Choose a supported input file or paste the supported text into the input area.
- Set the options shown for this tool and check that the input is the file type named on the page.
- Click Convert and read the output preview, status message, and any warnings.
- Download the result, then test it in the destination workflow before replacing the source.
Use cases
The validator helps caption editors, localization teams, video producers, teachers, accessibility reviewers, and support staff handle routine file checks. It is useful when a file came from several different tools and the next person needs a quick explanation of what is wrong. The report can also help a developer reproduce an upload failure by identifying a bad time line or an empty cue. Use it before delivery to reduce avoidable back-and-forth, then complete the platform-specific review separately.
A small browser converter is a good fit for a one-off task, a sample file, a review handoff, or a format check. It is less suitable for an unattended batch pipeline when the file set is large or the output needs a strict schema, printer profile, codec guarantee, or audit trail. For those workflows, keep the mapping and validation rules in the system that owns the data.
Output format
The output is a plain-text validation report. It identifies the detected format, counts parsed cues, gives a basic status, and lists issues with cue numbers or line references where available. The check does not rewrite the source file. It does not judge language quality, speaker accuracy, reading speed, audio sync against a video, font rendering, or platform-specific metadata. Save the report for review if another person needs to see why a subtitle file was returned for correction.
The expected result is .report output or the downloadable result described on this page. Source-specific details can change when the input format has no direct equivalent for layout, metadata, styling, timing, searchable text, color, or codec behavior. Review the actual download instead of relying only on the file extension.
Privacy
Validation runs on the text supplied to the page and does not require an upload to a caption vendor. Subtitle files can contain private conversations, paid course material, or licensed dialogue, so permission still matters. Use a redacted sample when a real file is sensitive. Check your browser and deployed site policy if the file belongs to a regulated workflow, and do not treat a local validation result as a legal or accessibility certification.
The page is designed around browser-side processing and does not require an AI API for the conversion described here. The site still loads page assets, and browser extensions, deployment settings, and organizational policy can affect a real environment. Do not use this wording as a legal privacy promise. Use the privacy policy and your own security review for confidential or regulated files.