Subtitle frame rate converter

Why frame rate changes the timing

Films are shot at 24 fps, usually released digitally at 23.976. In PAL countries, film used to be played at 25 fps, simply speeding everything up by about 4.3% instead of converting frames. A two-hour film at 23.976 fps runs about 1 h 55 min at 25 fps. Subtitles timed for one version therefore drift by minutes on the other.

The fix is to multiply every time by the ratio of the two rates. Going from 23.976 to 25 fps, each time is multiplied by 23.976 ÷ 25 ≈ 0.95904, so a line at 1:00:00 moves to about 57:32.5.

How to use the subtitle FPS converter tool

1. Load the subtitle file. Any supported format.
2. Enter the two frame rates. “Subtitles were made for” is the source; “Your video is” is the target. Pick from the list or type a value.
3. Apply. All cue times are rescaled. The status confirms the conversion.
4. Check and download. If the start is now offset by a constant amount, follow up with a shift.

Settings explained

Common rates

23.976 (film on digital), 24 (cinema), 25 (PAL), 29.97 (NTSC), 30, 50, 59.94 and 60.

Do not know the rates?

Use two-point resync instead: it measures the stretch directly from the video.

Converting the other way

Going from 25 fps subtitles to a 23.976 fps video, every time is multiplied by 25 ÷ 23.976 ≈ 1.04271, so cues move later and the file gets longer.

How to find your video’s frame rate

In VLC use Tools → Media Information → Codec. On Windows, right-click the file → Properties → Details. On a Mac, use QuickTime’s Movie Inspector. The subtitle file’s rate is often in its file name or release notes.

Frame rate and MicroDVD

MicroDVD .sub files store frames rather than times. Set the frame rate when you load them on the SUB to SRT page instead.

Troubleshooting

Now it drifts the other way

You swapped the two rates. Undo and apply again with the values reversed.

Still slightly off throughout

Combine with a constant shift; releases often differ in intro length too.

Frequently asked questions