Change Speed

Slow down or speed up a video or audio, keeping voices natural.

Processed in your browser — files never leave your device

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About Change Speed

Make a video or audio file slower or faster, from 0.25× to 4×. Voices can keep their natural pitch, or change with the speed for the classic slow-motion and fast-forward sound.

How Change Speed works

Change Speed plays your video or audio slower or faster, from 0.25× to 4×. With "Keep voices natural" ticked, the sound is time-stretched so voices keep their normal pitch; untick it for the classic effect where slow sounds deep and fast sounds high.

For videos, the frames are re-timed and the video is re-encoded as H.264, so it plays smoothly at the new speed; this runs on your device and takes longer for long videos. MP4, MOV, MKV and M4V keep their format, other videos become MP4, and audio files keep theirs.

When to use Change Speed

  • Make a slow-motion clip from a sports or dance video.
  • Speed up a long lecture, tutorial or voice message to save time.
  • Make a time-lapse-style fast version of a video.
  • Slow down a song or lesson to practise along with it.

How to use Change Speed

  1. Add your file. Drop a video or audio file into the box above.
  2. Choose the speed. Pick a common speed or use the slider; the new length is shown. Choose whether voices stay natural.
  3. Apply and download. Click Change speed, play the result and download it.

Options explained

Speed
Below 1× is slower, above 1× is faster. 2× halves the length; 0.5× doubles it.
Keep voices natural
On: same pitch at any speed. Off: pitch follows the speed, like a tape.
Videos
Re-encoded to H.264 so they play smoothly at the new speed.

Frequently asked questions

Why does slow motion look a little jerky?

Slowing down shows each frame for longer. Videos filmed at a high frame rate (60 fps or more) give the smoothest slow motion.

Can I change the speed of only part of a video?

This tool changes the whole file. Trim the part first with Trim Video, then change its speed.

Is my file uploaded?

No. The speed is changed in your browser.

Is Change Speed free?

Yes. Change Speed on DocEpic is free, with no sign-up, no watermark and no limit on how often you use it. The site is supported by ads.

Are my files safe with Change Speed?

Yes. Change Speed runs entirely in your web browser, so your files never leave your device and are never uploaded to us.

Do I need to install any software?

No. Change Speed works in any modern browser on Windows, macOS, Linux, Android and iPhone.

Is there a file size limit?

Files up to 1024 MB are accepted. Because the work happens on your device, very large files depend on your device's memory.

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