What does an SRT subtitle checker do?
An SRT subtitle checker reviews the structure and readability of SubRip subtitle files. It can flag malformed timecodes, cues with invalid durations, caption overlaps, unusually fast reading speed, overlong lines, excessive line counts, and numbering problems.
These checks are useful for video editors, YouTube creators, subtitlers, translators, localization teams, and anyone preparing caption files for review or delivery. A file can open correctly in a player while still containing readability problems.
What is CPS in subtitles?
CPS means characters per second. It estimates how quickly a viewer must read the visible caption text during its display time.
For example, a caption with 40 visible characters shown for two seconds has a reading speed of approximately 20 CPS. Actual reading comfort depends on language, audience, vocabulary, and context, so adjust the threshold for your particular project.
Why subtitle timing and line length matter
A caption that disappears too quickly can be difficult to read. Overlapping captions may cause two cues to appear simultaneously, although some projects intentionally use overlapping speaker cues. Very long lines can also make subtitles harder to follow on small screens.
Use the checker to locate likely problems. Always compare important findings with the final video and the style guide for your project. This tool checks text structure and timing; it cannot prove that captions match the spoken dialogue or are synchronized correctly to audio.
Frequently asked questions
Does this subtitle checker upload my file?
No. File reading and subtitle analysis take place locally in your browser. The page does not upload your subtitle text to a server.
Can I check WebVTT files as well as SRT?
Yes. The checker accepts SRT and WebVTT text and file formats. The downloadable normalized output is SRT, so WebVTT-specific cue settings are not retained.
Does a clean report guarantee platform approval?
No. A clean report means the file passed the enabled checks. Platforms, clients, languages, and projects may have different technical and editorial requirements.
Does the tool automatically rewrite captions?
No. It reports potential issues and offers a downloadable report. Its numbered SRT export normalizes cue numbering and time formatting, but does not rewrite caption text or automatically change cue timing.
Why does the checker flag a subtitle overlap?
It flags a cue that starts before the previous cue has finished. This may be an error, but overlapping speaker captions can be intentional, so review the video before changing the timing.
What does the AI fix prompt do?
It copies a prompt that explains the reported issues. It does not send your subtitle file to an AI service. You decide whether to paste the prompt and your subtitle content into another tool.