What gets changed when converting VTT to SRT?
SRT is a simpler format, so the conversion removes web-only features: the WEBVTT header, NOTE comments, STYLE blocks, cue identifiers, and positioning settings like align:start. Timestamps switch from dot milliseconds to commas, and every cue gets a sequential number, which SRT requires and VTT does not.
Voice and class tags (<v Speaker>, <c.classname>) are stripped from the text, since SRT players render them as literal text. Basic tags like italics survive, and your caption wording and timing are never altered.
Common reasons you need SRT instead of VTT
Desktop editors like Premiere Pro and DaVinci Resolve import SRT for caption tracks. Media players, smart TVs, and translation/localization workflows are also SRT-first. If you downloaded captions from a web platform and your next tool rejects them, this conversion is usually the missing step.
For short-form social video the cleanest path is skipping sidecar files entirely: Wavcut transcribes on your iPhone and burns styled, word-timed captions into the export, so the video carries its own captions on every platform.