How to speed up or slow down a video on iPhone
The Photos app can only slow down clips you shot in Slo-mo — it can't speed up a regular video or slow down one filmed at normal speed. Video Grid Collage changes the speed of any video from 0.25× to 5×, and different clips in one collage can even play at different speeds.
Step by step
Open the video
In Video Grid Collage (free on the App Store), tap + on the start screen, choose Image or Video and pick your clip.
Select the clip and tap Speed
Tap the video on the timeline, then Speed.
Set the speed
Go below 1× for slow motion, down to 0.25×, or above it to speed the clip up, up to 5×. The clip gets longer or shorter on the timeline as you change it.
Trim what you don't need
Cut the start and end so the clip gets straight to the action.
Fix the sound
Voices sound unnatural at high speed. Mute the clip under Sound and add music with Insert → Audio instead.
Export
Export up to 4K at 60 fps and share it.
Speed tricks that look good
- Slow motion looks smoothest from footage recorded at 60 fps or in the Camera's Slo-mo mode; 30 fps clips slowed to 0.25× look choppy.
- Speed up the boring middle of a process — cooking, cleaning, drawing — and keep the result at normal speed.
- In a collage, put the fast version and the real-time version side by side for an instant comparison.
- Combine speed with Reverse for rewind-style effects.
Try it yourself — free
Video Grid Collage · 4.9 on the App Store · 100 layouts, up to 100 clips in one collage