Subtitle Timing Calculator

This calculator checks whether a subtitle's on-screen timing gives viewers enough time to read it comfortably, using metrics common in professional subtitling: Characters per Second (CPS) and Words per Minute. Characters per Second is Character Count divided by Display Duration, and Character Count and Display Duration move it by comparable magnitude -- a longer display time lowers CPS, while more characters in the same duration raises it. Words per Minute and Reading Speed are computed with the identical formula (Words in Subtitle divided by Display Duration, times 60); they're reported separately because the subtitling industry describes reading pace in both units depending on convention, even though the two numbers will always match here. Standards Compliant checks two thresholds commonly cited in professional subtitling guides: a maximum of roughly 20 characters per second -- the ceiling widely associated with adult-programming subtitle standards, with a more conservative 17 CPS often cited as more comfortable -- and no more than two lines on screen at once.

Number of Lines and Words in Subtitle, notably, do not affect the Characters per Second figure at all, even though Number of Lines still factors into whether the subtitle is flagged compliant. Recommended Duration suggests how long the subtitle should stay on screen at a more conservative 15 CPS pace. This calculator treats every character as equally easy to read; it does not check actual characters-per-line against the roughly 42-character-per-line limit common in professional standards, and it does not evaluate punctuation or reading complexity.