iPhone slow motion is built into the Camera app — you switch to Slow-Mo mode before you record, not after

The Camera app on every iPhone has a Slow-Mo mode that records video at a higher frame rate than normal, so when you play it back at standard speed, the action appears slowed down. You cannot slow down a video you already shot — you have to record in Slow-Mo mode from the start. The process takes about 10 seconds once you know where to look.

Slow-Mo mode records at either 120 frames per second (fps) or 240 fps depending on your iPhone model and which resolution you choose. The higher the frame rate, the more storage the video uses, but the smoother the slow motion appears. A 10-second Slow-Mo video at 240 fps takes up roughly 350 to 400 MB of space.

Key Takeaways

  • Open the Camera app, swipe left to find Slow-Mo mode, and tap the red record button to start capturing — the mode is there before you record, not added afterward.
  • Your iPhone records at either 120 fps or 240 fps; higher frame rates use more storage but produce smoother slow-motion playback.
  • After you record, the video saves to your Photos app as a normal video file that you can trim, share, or edit in other apps.
  • You can adjust which parts of a Slow-Mo video play in slow motion and which play at normal speed by editing the video in the Photos app.

How to record a video in Slow-Mo mode

Open the Camera app on your home screen or lock screen. At the bottom of the screen, you will see a row of mode labels: Photo, Portrait, Panorama, Video, and Slow-Mo. Swipe left across these labels until Slow-Mo is highlighted in yellow. The word "Slow-Mo" will appear in the center of the screen.

Hold your iPhone steady and tap the red record button at the bottom center of the screen. The button will change to a red square, and a timer will appear showing how long you have been recording. When you are done, tap the red square to stop. The video saves automatically to your Photos app in the Recents album.

Slow-Mo videos look normal when you first watch them — the entire clip plays in slow motion. If you want parts of it to play at normal speed, you can edit it after recording (see the section below on editing).

Understanding frame rates and storage on different iPhone models

Newer iPhones (iPhone 12 and later) record Slow-Mo at 240 fps in 1080p resolution or 120 fps in 4K resolution. Older models (iPhone 11 and earlier) typically record at 120 fps in 1080p or 240 fps in 1080p depending on the specific model. The Camera app does not show you the frame rate — it just says "Slow-Mo" — so if you need to know your phone's exact specs, check Apple's technical specifications for your model number.

Higher frame rates and higher resolutions both increase file size. A 10-second video at 240 fps in 1080p uses roughly 350 to 400 MB. The same 10 seconds at 120 fps uses about 150 to 200 MB. If storage is tight on your phone, record shorter clips or delete Slow-Mo videos you do not plan to keep.

How to edit a Slow-Mo video after recording

Open the Photos app and find the Slow-Mo video you just recorded. Tap Edit in the top right corner. You will see a timeline at the bottom with a yellow bar underneath — the yellow bar shows which parts of the video are in slow motion.

Drag the edges of the yellow bar left or right to change which sections play in slow motion and which play at normal speed. For example, if you recorded a jump, you might want the takeoff and landing in slow motion but the flight in normal speed. Adjust the yellow bar to cover only those moments, then tap Done to save your changes.

The edited video saves over the original, so if you want to keep both versions, make a duplicate first. Tap the video, tap the three dots in the top right, and select Duplicate before you edit.

Sharing and exporting Slow-Mo videos

Once you have recorded and edited your Slow-Mo video, you can share it directly from the Photos app. Tap the video, then tap the Share button (a box with an arrow pointing up). Choose how you want to send it: Messages, Mail, AirDrop, or any other app installed on your phone.

If you want to use the video in another app like iMovie or a third-party video editor, tap Share and select Save Video or Save to Files. The video exports as an MP4 file that any video app can open. The file size is the same as the original — exporting does not compress it.

Some social media apps like Instagram or TikTok accept Slow-Mo videos, but they may convert the frame rate when you upload. Test with a short clip first to see how the platform handles it.

Why Slow-Mo videos use so much storage

Slow-Mo records more frames per second than normal video. A standard video records at 30 fps; Slow-Mo records at 120 or 240 fps. That means for every one second of real time, Slow-Mo captures four to eight times as much data. A 10-second Slow-Mo clip contains the same amount of visual information as a 40 to 80-second normal video, which is why the file is so large.

If you regularly record Slow-Mo videos, consider offloading old ones to cloud storage (iCloud, Google Drive, or another service) or a computer. This frees up space on your phone without deleting the videos permanently.

Frequently Asked Questions

Can I slow down a video I already recorded in normal mode?

No, not with the built-in Photos app. You would need a third-party video editor like iMovie, Adobe Premiere Rush, or CapCut. Those apps can slow down normal video, but the result will not look as smooth as true Slow-Mo because the phone did not capture enough frames. Slow-Mo mode is the only way to get professional-looking slow motion on an iPhone.

How much storage does a one-minute Slow-Mo video use?

Roughly 2 to 2.5 GB, depending on your iPhone model and resolution. A one-minute Slow-Mo video at 240 fps in 1080p uses about 2.1 GB. If you record frequently, you will fill your phone's storage quickly, so plan to move videos to a computer or cloud storage regularly.

Does Slow-Mo work in low light?

Yes, but the video will be grainier and darker than in daylight. Slow-Mo records at a faster frame rate, which means each frame captures less light. If you are recording indoors or at night, move closer to a light source or record outdoors if possible. The Camera app will warn you if the light is too low.

Can I change the frame rate after I start recording?

No. You choose the frame rate (120 or 240 fps) by selecting Slow-Mo mode before you record. Once you tap the record button, the frame rate is locked. If you want a different frame rate, stop recording, swipe back to Slow-Mo mode, and start a new clip.

What is the difference between 120 fps and 240 fps?

240 fps captures twice as many frames per second, so the slow-motion playback is smoother and more detailed. The trade-off is that 240 fps files are roughly twice as large. For most everyday slow-motion videos (sports, water splashes, pets), 120 fps looks good and saves storage. Use 240 fps only if you need extremely smooth motion or plan to edit the video heavily.