Quality you can check
The quality tool reads your subtitle and gives you a report. It changes nothing in the file, and the report names every limit it used.
Reading speed
Characters per second and words per minute over your limit.
Durations
Cues shorter or longer than your bounds, cues with no length, and cues that overlap the next one.
Lines
More lines in a cue than you allow, or a line longer than your limit.
Empty cues
Cues with no text.
Check against a standard
Pick a standard and the report judges your file by its limits, or set your own.
Netflix English Timed Text
The limits from the Netflix style guide for English subtitles. The report cites the guide.
Web video
Subtools defaults for online video. The report says these numbers are ours.
Same file, same result
The conversion, timing, cleaning, merge and edit tools give the same output for the same file and settings every time, so you can check one and trust the next. Translation and transcription are written by a model, so read those results before you use them.