Timecode
Frames ↔ timecode ↔ seconds at any frame rate. Retime between rates, check slow-mo speed, measure in/out durations.
01 · Frame rate
02 · Convert
Type in any field, the other two follow. Timecode takes 01:02:03:04, 2:12 (seconds:frames) or just digits 1020304.
03 · To another rate
Same duration = moving a cut to a new timeline rate. Same frames = conforming footage (shoot 60, play at 24 → 40% slow-mo).
04 · Duration
Out is exclusive, the way Premiere, Resolve and After Effects count. If your out point is the last frame you keep, add 1 frame.