Subtitle Sync
Fast. Private. Perfect.
Fix out-of-sync subtitles. Shift all timing by a fixed offset, or use two-point calibration to correct speed and drift.
Drag & drop your subtitle file here
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SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT
How It Works
Select your subtitle file that is out of sync.
Choose Time Shift for a fixed offset, or Two-Point Calibration for speed/drift correction.
For Time Shift: enter how much to delay or advance all cues.
For Two-Point: enter the current and correct timestamps for two reference cues.
Click Sync and download the corrected subtitle file.
Why Choose AllSubConverter?
Your Privacy Matters
Everything runs in your browser. Your files are never uploaded.
Lightning Fast
Optimized processing engine converts files in seconds.
Truly Unlimited
No file size limits. No daily limits. Completely free.
Works Everywhere
Works on Windows, Mac, Linux, iOS, Android - any modern browser.
Key Features
Common Use Cases
Fixed Offset
Subtitles play 2 seconds too early or too late. Use Time Shift to delay or advance all cues by the same amount.
Gradual Drift
Subtitles start in sync but gradually drift apart over time. Two-Point Calibration corrects both the offset and the speed factor.
Frame Rate Mismatch
Subtitles made for 24fps video played on 25fps video. The speed factor correction in Two-Point mode fixes this automatically.
PAL/NTSC Conversion
Subtitle timing is off due to PAL/NTSC conversion. Two-point calibration recalculates timing for the new frame rate.
Opening Credits
Your subtitles start after the opening credits but the video does not. Shift all cues to match the video start.
Multi-Source Sync
Subtitles from one release do not match another release of the same film. Use two-point calibration to realign.
Frequently Asked Questions
Subtitle syncing adjusts the timing of subtitle cues so they align correctly with the video audio. This tool supports two modes: a fixed time shift for constant offset, and two-point calibration for correcting speed differences and drift.
You provide two reference points: the current time and the correct time for two cues. The tool calculates a linear transformation (t_new = a * t_old + b) that maps old times to new times, applying the correction uniformly to all cues.
Use HH:MM:SS,mmm format, e.g., 00:01:30,000 for 1 minute 30 seconds. You can also use shorter formats like MM:SS.mmm.
Use Time Shift when all subtitles are off by the same amount throughout the video. Use Two-Point Calibration when subtitles start correctly but gradually drift apart, which indicates a speed/frame-rate mismatch.
Yes. Select the Earlier direction and enter the amount to advance. Times that would become negative are clamped to 0.
Input: SRT, VTT, ASS, SSA, LRC, SBV. Output: SRT or VTT.