Slow-motion clips on iPhone record at 120 or 240 frames per second, which makes them 4-8x larger per second than normal video, and a single 30-second slo-mo can run 200-400MB. Time-lapse clips compress better but stack up fast. The quickest way to find them is Photos > Albums, then scroll to Media Types and tap Slo-mo or Time-lapse to review every clip in one place.
TL;DR
- Slo-mo records at 120/240fps, so a short clip can be several hundred MB.
- Find them all under Photos > Albums > Media Types > Slo-mo and Time-lapse.
- You can "convert" a slo-mo to normal speed in Edit, but that does not shrink the file on its own.
- iOS lets you review and delete; it has no built-in way to re-encode these to a smaller size.
- Deleted clips sit in Recently Deleted for ~30 days, so back up keepers before clearing.
Why are slo-mo and time-lapse clips so large?
Slow motion captures many more frames per second so playback can be smoothed out. At 240fps your phone writes roughly four times the frames of standard 60fps video, and bitrate scales with it. That is why a 20-second slo-mo can be bigger than a minute of regular footage.
Time-lapse works the opposite way at capture (it samples frames over a long period) but the finished clip can still be hundreds of MB if it ran for a long event. Both formats are easy to forget because you rarely rewatch them.
How do I find every slo-mo and time-lapse on my iPhone?
iOS groups these by format, which makes a cleanup pass simple.
- Open Photos and tap the Albums tab.
- Scroll down to the Media Types section.
- Tap Slo-mo to see every slow-motion clip, or Time-lapse for those.
- Tap Select (top right), then tap clips you no longer want.
- Tap the trash icon to delete the selection.
Work newest-to-oldest or sort by what you recognize. Most people find a handful of test clips and duplicates they can remove immediately. To confirm which are the actual space hogs, cross-check with find and delete large videos without deleting photos.
Should I convert a slo-mo instead of deleting it?
If you want to keep the moment but not the slow-motion effect, you can change where the slow part starts and ends, or remove it entirely.
- Open the slo-mo clip and tap Edit.
- On the speed track below the filmstrip, drag the vertical bars together to shrink the slow section, or move them to the end to play at normal speed.
- Tap Done.
Important: this changes playback, not file size. The full high-frame-rate data is still stored. To genuinely reduce the size after converting, you need to re-export at a lower frame rate using a compressor, as in how to compress videos on iPhone without losing quality.
What iOS does natively, and where it stops
Natively, iOS sorts these clips into the Media Types albums, lets you batch-select and delete, and lets you adjust the slow-motion timing in Edit. That covers finding and removing them, which is most of the win.
Where it stops: there is no native re-encode to a smaller frame rate, no "keep but shrink" option, and converting a slo-mo to normal speed in Photos does not free the underlying storage. For that you need a third-party tool.
What this cannot do, and how to stay safe
The Media Types albums show clips you still have on the device or in iCloud; they cannot recover clips already deleted, and editing slow-motion timing will not reclaim space by itself.
Before a cleanup sweep, back up the clips you care about. Anything you delete lands in Photos > Albums > Recently Deleted and is recoverable for about 30 days before permanent removal. If you shoot a lot of slo-mo going forward, consider dialing back capture quality, explained in 1080p vs 4K iPhone camera settings. And if your storage is full with no obvious cause, see iPhone storage full but nothing to delete.
FAQ
How much space does a slow-motion video take?
At 240fps a 30-second slo-mo commonly runs 200-400MB, roughly 4-8x a normal clip of the same length. Several test slo-mos can quietly use over a gigabyte.
Does converting a slo-mo to normal speed save storage?
No. Editing the speed in Photos only changes playback; the high-frame-rate data stays on the device, so the file size is unchanged.
Where do deleted slo-mo and time-lapse clips go?
They move to Photos > Albums > Recently Deleted for about 30 days, then they are erased for good. Back up any you want to keep before deleting.
Want the largest clips found for you automatically? Cleanor for iPhone surfaces big slo-mo, time-lapse, and regular videos so you can clear them in one pass, and our free up iPhone space guide covers the safe order to do it.