Convert subtitles from 25 fps to 23.976 fps
Subtitles made for a 25 fps release, common for European TV and DVDs, start out close and then fall further out of step on a 23.976 fps copy of the same film. Converting the frame rate multiplies every time by 25 / 23.976, so the subtitles stretch to the longer running time. Upload the file or a ZIP of a season and download it re-timed in its own format. Jobs with up to 3,000 lines are free in full; bigger jobs are $5, paid once.
- Every start and end multiplied by the exact ratio; 23.976 is used as 24000/1001
- Rates: 23.976, 24, 25, 29.97, 30, 50, 59.94 and 60, in either direction
- Works on a whole ZIP or season in one job
- Text, order and formatting unchanged; ASS styles kept
- Each file returned as name.synced plus its extension, or as SRT
Why 25 and 23.976 do not match
Most films are shot at 24 frames per second and released at 23.976 for video. Television in Europe ran at 25, so for broadcast and many European DVDs the film was simply played faster, about 4 percent, and the sound was sped up with it. A 100-minute film runs about 96 minutes at 25 fps. Subtitles timed to that faster version are correct at the start and fall behind your 23.976 copy more each minute: a few seconds off after one minute, tens of seconds off later on.
No single shift can fix this. Each time has to be multiplied by 25 / 23.976, about 1.0427. The converter uses the exact value, 25 divided by 24000/1001, so there is no rounding drift at the end of a long film.
How to tell this is your problem
- The first lines are roughly right, and the gap grows steadily through the film
- The subtitles appear earlier and earlier than the speech on a 23.976 video
- The subtitle file came from a European TV recording or DVD release
- The running time of the release the subtitles were made for is about 4 percent shorter than yours
Other combinations, and a caution
The same option works the other way, 23.976 to 25, for subtitles made for a film release that you are watching from a European source, and for 24 to 25. Choose what the subtitles were made for, then what your video is.
Be careful with 29.97. A film shown at 29.97 fps in North America is usually the same length as the 23.976 version, because frames are repeated rather than the film being sped up, so converting between those two rates would put correct subtitles out of sync. Compare the running times first: if they match, you need a shift, not a frame rate change. If you are unsure, the stretch option, using two lines you check, fits any steady drift.
How the tool works, what it costs and how your files are handled is on the Fix Subtitle Sync page; prices for every tool are on the pricing page.
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Questions and answers
Can ChatGPT convert subtitles from 25 to 23.976 fps?
It knows the ratio and can apply it to a few lines. A full film means multiplying and retyping well over a thousand time codes, and chat replies tend to stop partway, round inconsistently or skip lines. This tool applies the exact ratio to every time in code.
Which way round do I choose the rates?
First the rate the subtitles were made for, then the rate of your video. For PAL subtitles on a film copy, that is 25, then 23.976.
Can I convert a whole season?
Yes. Upload up to 50 files or a ZIP; every episode is converted with the same rates and comes back in one ZIP.
What does it cost?
Free in full for jobs with up to 3,000 lines in total, usually enough for one film. A season or bigger job is $5, paid once, for up to 50,000 lines. Unlimited is $19 a week.
The subtitles are still off by a fixed amount after converting. Why?
The two releases may also start at different points. Run the converted file through the shift option with the remaining offset.