Free Subtitle Speed Changer - Stretch, Compress & Resync Subtitles
Scale subtitle timing to match sped-up or slowed-down video. Convert between frame rates, apply speed factors, or use two-point linear resync for perfect synchronization.
Upload Subtitles
Upload your subtitle file or paste content directly
Speed FactorActive
Multiply all timings by a speed factor or use a frame rate preset
Factor < 1.0 = subtitles play faster (compressed)
Factor = 1.0 = no change
Two-Point Linear Resync
Provide two reference points to stretch and shift subtitles precisely
How to Use the Subtitle Speed Changer
📁 Upload Your File
Drag and drop your subtitle file or paste text directly. Supports SRT, VTT, ASS, SUB, SBV, and STL formats.
⚡ Choose Your Method
Use a Speed Factor to scale all timings uniformly, or Two-Point Sync to precisely resync by providing two known reference points.
🎯 Frame Rate Presets
Quickly convert between common frame rates (23.976, 24, 25, 29.97 fps) using built-in presets. Perfect for PAL ↔ NTSC conversions.
💾 Download Results
Preview the adjusted timings, compare first and last subtitle changes, then download your perfectly synced file.
Features
Speed Factor Scaling
Multiply all subtitle timings by any factor. Speed up, slow down, or apply precise frame rate conversion ratios.
Two-Point Linear Resync
Provide two known reference points and the tool calculates the perfect scale and offset to resync every subtitle line.
Frame Rate Presets
One-click presets for common conversions: 23.976↔25, 24↔23.976, 25↔29.97 fps and more.
Frequently Asked Questions
What is the difference between shifting and stretching subtitles?
Shifting adds or subtracts a constant offset to all timings (e.g., +2 seconds). Stretching scales timings by a factor, which means the adjustment grows proportionally over time. Use shifting when subtitles are consistently early/late; use stretching when they drift further out of sync as the video progresses.
When do I need frame rate conversion?
When subtitles were created for a video at one frame rate (e.g., 25 fps PAL) but your video runs at a different rate (e.g., 23.976 fps NTSC). This causes subtitles to gradually drift out of sync. Use the appropriate frame rate preset to fix it instantly.
How does two-point sync work?
You identify two moments in the video where you know the exact correct timing. Enter the current subtitle time and the desired time for both points. The tool calculates a linear transformation (scale + offset) that maps all subtitle timings to match your video perfectly.
What speed factor should I use?
For frame rate conversions, use the built-in presets. For custom adjustments, a factor of 1.0 means no change, greater than 1.0 stretches (slows down), and less than 1.0 compresses (speeds up). For example, if your video is 5% faster, use a factor of 0.95.
Is the subtitle speed changer free?
Yes, completely free with no registration required. Process unlimited files with no watermarks or restrictions.