Change Video Speed
Speed up or slow down any video — 0.25× to 4× — free, client-side, no upload.
100% in your browser
No watermark
No sign-up
How it works
- Drop or select your video file.
- Choose a playback speed: 0.25×, 0.5×, 0.75×, 1.5×, 2×, or 4×.
- Click "Change Speed" — FFmpeg re-encodes the video entirely in your browser.
- Your adjusted MP4 downloads automatically.
Frequently asked questions
- Is my video uploaded to a server?
- No. All processing happens locally in your browser using WebAssembly. Your file never leaves your device.
- What video formats are supported?
- Any format your browser can handle as input, including MP4, WebM, MOV, MKV, and AVI. The output is always saved as MP4.
- Will the audio be adjusted too?
- Yes. Both video and audio are re-timed to match the chosen speed. The audio pitch is preserved using the atempo filter.
- Why does re-encoding take longer than trimming?
- Changing speed requires every video frame to be decoded and re-encoded. This takes more time than a simple stream copy, but the result plays correctly in all players.
- Can I slow down below 0.25× or speed up beyond 4×?
- Not with the current preset options. Those extremes are the practical limits for keeping audio intelligible and video smooth.