SRT Subtitle Timing Adjuster
Your subtitle file is out of sync with the video. Upload it, set an offset in milliseconds or seconds, and download the corrected file. Drift correction handles frame rate mismatches too. Nothing uploaded.
Drop your .srt file here
or click to browse · .srt files only
Time offset
Use {original} for original filename, {offset} for offset value.
Frame-rate drift correction
Apply a preset when subtitles drift progressively further out of sync throughout the video - a sign of a frame-rate mismatch rather than a fixed offset.
| # | Original timecode | Adjusted timecode | Text |
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Learn more: subtitle offset vs drift
Offset and drift are two different problems
A fixed offset moves every subtitle by the same amount, which fixes a file that is two seconds early or late from the first line to the last. Drift grows over the runtime, so the start can match while the ending is seconds out.
The tool applies both with one formula: new time = original time x drift multiplier + offset in milliseconds. A multiplier of 1.0 leaves timing alone, and the tool keeps it between 0.01 and 100.
Frame rate mismatch is a common cause
SubtitleEdit's synchronization guide says a frame rate mismatch or bad source file makes subtitles "drift slowly over time", while a fixed offset shows up across the whole video. For drift it recommends syncing using two points, the start and the end.
You can do the same sum by hand. If a file timed for 23.976 fps is played against a 25 fps video, the multiplier is 23.976 / 25 = 0.95904. A line at one hour (3,600,000 ms) then moves to 3,452,544 ms, about 147 seconds earlier.
Working out both values from two lines
Pick one line near the start and one near the end, and note where each should be. Say the first line is at 60 s and should be at 62 s, and the last is at 3,600 s and should be at 3,590 s. The multiplier is (3,590 - 62) / (3,600 - 60) = about 0.99661.
The offset is then 62 - 60 x 0.99661 = about 2.2 s, or 2,203 ms. Enter the multiplier and the offset together.
FAQ
My subtitles start in sync but end badly out of sync. What is wrong?
That is drift, not offset. Use the drift multiplier, with a fixed offset if the start is also off.
Why would a video have drifting subtitles?
A frame rate mismatch between the subtitle file's source and your video is a common cause. A bad source file can do it too.
Can I fix a bad start and drift in the same pass?
Yes. The offset and multiplier apply together to every timestamp, so one adjustment covers both.
How to fix SRT subtitle timing
Upload your .srt file and enter the offset in milliseconds. Use a positive number to delay subtitles (they appear later) and a negative number to advance them (they appear earlier). The slider covers -60 s to +60 s, or type any value directly.
For progressive drift - where the first subtitle is correct but the last is several seconds off - use a drift multiplier or pick an FPS preset. This applies a linear scale to all timestamps, correcting frame-rate mismatches between the subtitle file and the video.