How to Slow Down or Speed Up a Video on iPhone

Slowing a moment down draws the eye to the action, while speeding a dull stretch up keeps a clip moving. Doing both within the same video, ramping the speed up and down, is where a dedicated tool really helps.

Can you do it with the built-in apps?

iMovie can change the speed of a whole clip, but ramping different sections, slow here and fast there, is fiddly, and the built-in tools do not always keep the audio natural. A tool built for speed control lets you set several sections in one clip and keeps the pitch corrected.

Step by step

Here is how to do it with Slow-Fast Motion.

1. Install Slow-Fast Motion and open the video you want to adjust.
2. You will see a speed graph beneath the clip. Drag a point down to slow a moment right down, or up to speed it up.
3. Tap Add Point to create more sections, so you can slow one part and speed up another in the same video.
4. Because the changes happen smoothly between points, the speed eases in and out rather than jumping.
5. Play back the clip to check the timing, and delete any point you want to redo.
6. Export at full resolution. Saving is free and there is no watermark.

Tips

• Slow a clip down to one-tenth speed to bring out detail in fast action, or speed it up to 10x for a time-lapse feel.
• The app corrects audio pitch, so slowed speech and music still sound right rather than dropping in tone.
• It handles portrait or landscape video and has no length limit, so longer clips are fine.

Frequently asked questions