Speed Up or Slow Down Your Video
Change video playback speed from 0.25x to 4x, with automatic pitch-preserving audio — all processed privately in your browser.
Drag and drop a video here, or click to browse
MP4, WebM, or MOV — up to 500MB
Upload a video to change its speed
About the Video Speed Changer
This free tool speeds up or slows down any video, from a subtle 0.75x to a dramatic 4x, while keeping audio pitch natural using FFmpeg's atempo filter. Everything runs locally in your browser via WebAssembly — nothing is uploaded.
Features:
- Speed range from 0.25x (slow motion) to 4x (fast forward)
- Pitch-preserving audio at every speed, powered by FFmpeg's atempo filter
- Optional silent output with the remove audio toggle
- Privacy-first — speed changes happen entirely on your device
How to Change a Video's Speed
- Upload an MP4, WebM, or MOV video file
- Pick a speed preset or fine-tune it with the slider
- Optionally remove the audio track entirely
- Click Change Speed, then preview and download the result
Frequently Asked Questions
Is this video speed changer really free?
Yes. There's no signup, no watermark, and no limit on how many videos you process — everything runs in your browser.
Does my video get uploaded to a server?
No. Speed changes happen entirely locally using FFmpeg compiled to WebAssembly. Your file never leaves your device.
What video formats can I upload?
MP4, WebM, and MOV (QuickTime) are supported, up to 500MB per file.
Does changing speed make voices sound chipmunky?
No. Unlike simply speeding up playback, this tool uses FFmpeg's atempo audio filter, which changes tempo without changing pitch. Voices stay at their natural pitch whether you slow a video down to 0.25x or speed it up to 4x — no chipmunk or slow-motion-growl effect.
Can I remove the audio instead of speeding it up?
Yes. Turn on the "Remove audio" toggle to export a silent video at your chosen speed, skipping audio processing entirely.
Why is 4x speed handled differently from 2x?
FFmpeg's atempo filter only accepts a single tempo change between 0.5x and 2x at a time. For speeds outside that range, this tool automatically chains multiple atempo stages together — for example, 4x speed becomes two consecutive 2x stages (atempo=2.0,atempo=2.0), and 0.25x becomes two consecutive 0.5x stages. You don't need to do anything; it happens automatically behind the scenes.
Privacy
Your video is processed entirely in your browser using WebAssembly. It is never uploaded, stored, or seen by our servers.