FPS subtitle converter
If the first cues are nearly right but the subtitles drift further out of sync the longer the video runs, the file was timed for a different frame rate. Multiplying every cue by the ratio (23.976 → 25, 25 → 29.97, PAL speed-up and back) puts it back on the timeline.
Drop an .srt / .vtt / .ass file here
or click to choose one · nothing leaves this page
Before / after
Frame durations
| Frame rate | One frame | Where it shows up |
|---|---|---|
| 23.976 fps | 41.708 ms | Film on Blu-ray / streaming (24p with pulldown) |
| 24 fps | 41.667 ms | Film, cinema, most festivals |
| 25 fps | 40.000 ms | PAL regions, European broadcast, DVD/Blu-ray in PAL |
| 29.97 fps | 33.367 ms | NTSC broadcast, US cable, many deliveries |
| 30 fps | 33.333 ms | Screen recordings, some web delivery |
| 59.94 fps | 16.683 ms | High frame-rate sport and gameplay capture |
How far off does each combination end up?
| Conversion | Timing factor | Drift per minute of video |
|---|---|---|
| 23.976 → 25 | 1.042709 | +2563 ms |
| 25 → 23.976 | 0.959040 | −2458 ms |
| 24 → 25 | 1.041667 | +2500 ms |
| 25 → 24 | 0.960000 | −2400 ms |
| 23.976 → 24 | 1.001001 | +60 ms |
| 29.97 → 30 | 1.001001 | +60 ms |
| 25 → 29.97 | 1.198800 | +11928 ms |
| 23.976 → 29.97 | 1.250000 | +15000 ms |
Positive drift = subtitles end up later than the picture (they were timed for a slower rate). Negative = earlier. Anything above roughly 100 ms per minute is impossible to hide with a fixed offset, which is why this page multiplies instead of shifting.
Retiming a whole series?
The studio re-times every open file at once, exports them as one ZIP and can hand you a CSV/JSON timing report to prove the result. Pro is a $9 one-time licence — lifetime, up to 3 devices — with a 7-day refund while the key is unactivated. Single-file retiming stays free, including export.
Questions people ask before using it
Why do subtitles drift more the longer the video plays?
The file was timed against a different frame rate than the video you are watching. Every cue is multiplied by the ratio between the two rates, so the error accumulates — 25 fps subtitles on 29.97 fps footage end up about 11.9 seconds out over a single minute of content.
Which frame rate do my subtitles belong to?
Whatever the cut they were authored against used. Watch the direction of the error: cues that run early and get worse mean the video rate is lower than the subtitle rate; cues that fall behind mean it is higher. The table above gives the expected drift for each combination, so you can match it against what you see.
Is this the same as a PAL speed-up fix?
Yes. 25 → 23.976 (or the reverse) is the classic PAL/NTSC case: about 4 percent fast or slow, which is 2.5 seconds of drift per minute — far too much for a fixed offset to fix.