How a synced lyrics file works
An LRC file is plain text. Each lyric line begins with a timestamp in minutes, seconds and fractions of a second, and a player jumps to that line when the song reaches that time. The format is simple enough to open in any text editor, which is why the same file works in car stereos, phone music apps, desktop players and karaoke software. Before the lines there can be header tags that describe the song, such as the title and the artist.
This tool builds that file from your own taps. You paste the words, press play and mark the moment each line starts. The page records the playback time at each tap, so the result is only as precise as your reaction, and the editing controls exist to tighten it. You can undo the last tap, nudge a line by a tenth of a second and slow the audio down while you work.