# Change Speed — Speed up or slow down a video on Mac

Speed up or slow down, with the audio pitch kept natural. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: Video. Runs on your Mac; nothing is uploaded.

Play a video at 0.25× to 4× speed. The audio is time-stretched so voices keep their natural pitch instead of sounding like chipmunks.

Page: https://www.onemactools.com/tools/change-video-speed · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Install FFmpeg once.** If it isn't installed, OneMacTools offers to install FFmpeg through Homebrew with one click.
2. **Drop your videos.** Add the clips you want faster or slower.
3. **Pick the speed.** Choose from 0.25× to 4× in the right-hand panel. 2× is selected to start with.
4. **Click Change.** The picture is sped up or slowed down, and the sound is time-stretched so voices keep their normal pitch.
5. **Watch the result.** The new copies, with the speed in the name, are saved in a new dated folder in Downloads › OneMacTools. Open them with the Preview (eye) button or Show in Finder. The originals don't change.

## Options
- **Speed:** 0.25×, 0.5×, 0.75×, 1.25×, 1.5×, 2× (the default) or 4×. Below 1× slows the video down and makes it longer; above 1× speeds it up and makes it shorter.

## Tips
- 1.25× or 1.5× is a comfortable speed for tutorials and talks. Voices stay clear and natural.
- For a time-lapse feel, use 4× and run the result through again for 16×.
- Slow motion from normal footage repeats frames, so 0.25× can look jerky. It looks smoothest on clips filmed at a high frame rate.
- Trim first if you only want part of the video sped up, then join the pieces with Merge Videos.
- Videos without sound work too; they're simply saved without an audio track.

## Questions
**How do I speed up a video on a Mac?**
Drop it onto Change Speed, choose 1.5×, 2× or 4×, and click Change. The faster copy is saved as a new file.

**How do I make a slow-motion video?**
Choose 0.5× or 0.25×. Footage filmed in slow-mo or at 60 fps looks smoothest when slowed down.

**Will voices sound like chipmunks?**
No. The audio is time-stretched rather than pitched up or down, so voices keep their natural pitch.

**Can I choose a speed that isn't in the list?**
Not directly, but you can run the result through again. For example, 2× then 1.5× gives 3×.

**Does changing the speed change the length?**
Yes. 2× halves the length and 0.5× doubles it.