Free tool
Subtitle Converter
Convert between SRT and WebVTT, shift every caption by an offset, reflow long lines to a character limit, or strip a file back to plain text. Everything runs in your browser, so nothing is uploaded.
Negative pulls captions earlier. Anything pushed before zero is clamped to the start.
42 characters over two lines is the usual broadcast limit. Netflix uses 42, most social captions sit nearer 32.
Captions taking longer than the edit?
CutFlow AI transcribes and styles captions inside Premiere Pro, locally, with no upload and no subscription.
SRT and VTT, what actually differs
Both formats list captions with a start time, an end time and some text. SRT separates seconds from milliseconds with a comma, WebVTT uses a full stop and starts the file with the word WEBVTT. VTT also allows styling and positioning cues that SRT has no way to express. Converting from VTT to SRT drops that styling, which is usually what you want when a file is headed into an editor.
Why captions get shifted
If a transcript was made from a file with a different start point, or from an export with a slate on the front, every caption lands late or early by the same amount. Shifting the whole file by that offset fixes it in one pass. Check the first and last caption after shifting, since a file that drifts rather than offsets needs retiming instead.
Line length and reading speed
Two lines of about 42 characters is the broadcast standard, and most platforms accept it. Social captions usually want less, nearer 32, because the text sits over a vertical frame. Reading speed matters as much as length: above roughly 20 characters per second viewers stop keeping up, which is a sign the caption needs splitting rather than shrinking.