Pick a format in one sentence
Sideloading into a player, maximum compatibility → SRT; web players (HTML5 track) or YouTube upload → VTT; fonts, colors, positioning, effects → ASS; downloaded from YouTube → SBV (convert to SRT to widen support); song lyrics, line-by-line singing → LRC.
Capability comparison
SRT: plain text + timing, no styling or positioning, the compatibility champion. VTT: text + timing, natively supported by browsers, can carry positioning and basic styling, dot before milliseconds. ASS: text + timing + full styling (fonts, colors, outlines, positioning, effects), timing to centiseconds. SBV: YouTube's minimal subtitle format, start and end on one line. LRC: lyrics format, start times only, no end times, no styling.
Paths between formats
Any of these convert both ways in the converter: reading supports srt, vtt, ass (including ssa), sbv, lrc, txt; exporting supports srt, vtt, ass, sbv, lrc, txt. The common routes each have their own guide: SRT to VTT, VTT to SRT, SRT to ASS, ASS to SRT, SBV to SRT, LRC to SRT.
What conversions lose
Converting to SRT always drops styling and positioning (SRT cannot hold them). Converting to ASS with this tool rebuilds a default style and does not keep the original one. LRC to SRT needs end times filled in (each line lasts until the next; the last gets 3 seconds). Timing values and text stay identical in every direction.