Convert subtitles from 29.97 fps to 23.976 fps
For subtitle files timed at a 29.97 fps NTSC frame count that need to match a 23.976 fps reference. Drop the file in below to rescale the timing.
Need a different frame rate? Use the full framerate converter →
When 29.97 → 23.976 fps is the right conversion
This is the reverse of the NTSC frame-count conversion: 23.976 = 29.97 × 0.8, so going the other way multiplies every timestamp by 29.97 / 23.976 = 1.25. It applies when a subtitle file's timing was built around 29.97 fps frame numbers — a frame-based .sub, or a wrong-fps export — and you need it on a 23.976 fps timeline.
As with the forward direction, remember that NTSC 3:2 pulldown does not change playback speed, so a time-based SRT made for a 29.97 fps NTSC broadcast is usually already correct against the 23.976 fps film. If your SRT drifts steadily, look at PAL (25 fps) first with 25 → 23.976. Reach for this page when the timings are genuinely scaled by the frame-count ratio.
Other direction: 23.976 → 29.97 fps.
FAQ
Is a big 25% shift normal here?
Yes — 29.97 and 23.976 differ by a full 1.25 times in frame count, so a genuine frame-count mismatch throws timings off dramatically and fast, not subtly. If your subtitles are only slightly and gradually off, this is the wrong tool; you likely want a PAL conversion or the Shift tool.
What does times 1.25 do?
It multiplies every timestamp by 29.97 / 23.976 = 1.25. A cue at 8:00 moves to 10:00. That undoes a timeline that was compressed by the inverse 0.8 factor.
Do time-based SRTs need this?
Rarely. NTSC pulldown preserves runtime, so 29.97 fps NTSC subtitles usually already line up with the 23.976 fps film. This page is mainly for frame-based files or mis-exported timings.