You can slow down video on iPhone using the built-in Photos app or the native Camera app, depending on whether you're working with a video you've already recorded or want to film in slow motion from the start.

The fastest route is the Photos app if the video already exists on your phone. Open Photos, find the video, tap Edit, then adjust the speed slider at the bottom of the screen. You can slow it down to 0.5x (half speed) or speed it up to 2x. When you're done, tap Done and choose Save as New Clip to keep the original.

If you want to record video in slow motion from the start, use the Camera app. Swipe to Slo-Mo mode before you record, then film normally. The phone automatically captures at a higher frame rate, which creates the slow-motion effect when you play it back. This method gives you the best quality because the phone is capturing more frames per second while you're recording, rather than stretching frames that were already captured at normal speed.

Key Takeaways

  • The Photos app lets you slow down any existing video to 0.5x speed or faster, and you can save the edited version without replacing the original.
  • The Camera app's Slo-Mo mode records video at a higher frame rate, which produces smoother slow-motion playback than editing a normal-speed video after the fact.
  • Editing in Photos takes seconds, but the result depends on the original video quality and frame rate.
  • Slo-Mo mode uses more storage because it captures more frames per second, so check your available space before recording long clips.

Using the Photos App to Slow Down Existing Video

Open the Photos app and locate the video you want to slow down. Tap the video to open it, then tap Edit in the top right corner. The editing toolbar appears at the bottom of the screen.

Look for the speed slider — it shows a number like 1x in the center, with a minus sign on the left and a plus sign on the right. Drag the slider to the left to slow the video down. You can go as low as 0.5x (half the original speed). Drag to the right to speed it up to 2x if you need to. Watch the preview as you adjust so you can see the effect in real time.

Once you're happy with the speed, tap Done at the bottom right. A menu appears asking whether you want to Save as New Clip or Save to Original. Choose Save as New Clip to keep both versions — the original and the slowed-down one. If you choose Save to Original, the slow-motion version replaces the original file.

Recording Video in Slow Motion with the Camera App

Open the Camera app and look at the row of mode buttons at the bottom of the screen. Swipe left through the modes until you reach Slo-Mo. The button shows a snail icon or the text "Slo-Mo" depending on your iPhone model.

Once you're in Slo-Mo mode, the frame rate appears at the top of the screen — usually 120 fps (frames per second) or 240 fps depending on your phone. Higher frame rates create smoother slow motion but use more storage. Press the red record button to start filming, and press it again to stop. The video saves to your Photos app automatically.

When you play back a Slo-Mo video, the entire clip plays in slow motion by default. You can edit it later in the Photos app to return parts of it to normal speed if you want — for example, to slow down only the middle section of a sports clip while keeping the beginning and end at normal speed.

Why Slo-Mo Mode Produces Better Results Than Editing

When you record in Slo-Mo mode, your iPhone captures 120 or 240 frames per second instead of the standard 30 fps. More frames means smoother playback when the video plays slower. If you slow down a normal-speed video in the Photos app, you're stretching the same number of frames across a longer time period, which can look choppy or blurry.

The trade-off is storage. A Slo-Mo video uses roughly twice as much space as a normal video of the same length because it contains twice as many frames. If your iPhone storage is nearly full, record in normal mode and edit the speed later. The result won't be as smooth, but it will work.

Editing Speed in Different Sections of the Same Video

You can make one part of a video slow and another part normal speed using the Photos app. Open the video in edit mode and look for the speed slider. Below the slider, you'll see a timeline with the video broken into segments.

Tap on a section of the timeline to select it, then adjust the speed slider for just that section. The unselected sections keep their original speed. This works best with Slo-Mo videos because you have more frames to work with, but you can do it with normal videos too. Save the result as a new clip when you're done.

Common Mistakes and How to Avoid Them

The most common mistake is expecting a normal-speed video to look as smooth as a Slo-Mo video after you slow it down. It won't. If smooth slow motion matters for what you're filming, use Slo-Mo mode while recording. Editing the speed afterward is a quick fix, not a replacement.

Another mistake is not checking storage before recording a long Slo-Mo clip. A 10-second Slo-Mo video can use 100 MB or more depending on resolution and frame rate. If you're planning to record several clips, delete old videos first or connect to Wi-Fi to back up your photos to iCloud.

Don't forget to save as a new clip if you want to keep the original. Tapping Save to Original overwrites the file permanently, and there's no undo.

Sharing and Exporting Your Slow-Motion Video

Once your video is edited, you can share it directly from the Photos app. Open the video, tap the share icon (a box with an arrow), and choose where to send it — Messages, Mail, social media, or another app. The slow-motion effect travels with the video.

If you need to export the video to your computer, connect your iPhone to a Mac or Windows PC and use the Photos app or Finder to copy the file. The slow-motion version saves as an MP4 file that plays on any device. Some older devices or apps may not recognize the slow-motion metadata, but the video itself will still play — it just won't be slow unless the app supports it.

Frequently Asked Questions

Can I slow down a video to less than 0.5x speed?

No, the Photos app's speed slider stops at 0.5x. If you need slower motion, you'll need a third-party video editing app like iMovie or Adobe Premiere Rush, which offer more granular speed control. These apps let you set custom speeds like 0.25x or 0.1x.

Does slowing down a video reduce the quality?

Slowing down a normal-speed video doesn't reduce quality, but it can look choppy because the phone is stretching fewer frames across more time. Slo-Mo videos look smoother when slowed because they were captured with more frames. Quality also depends on the original resolution — a 4K video will look better slowed down than a 1080p video.

How much storage does a Slo-Mo video use compared to normal video?

Slo-Mo video at 120 fps uses roughly twice as much storage as normal video at 30 fps. A 1-minute Slo-Mo clip can use 200–300 MB depending on resolution and lighting, while a 1-minute normal video uses 100–150 MB. 240 fps Slo-Mo uses even more.

Can I change the speed of just part of a Slo-Mo video back to normal?

Yes. In the Photos app edit screen, tap different sections of the timeline and adjust the speed slider for each one independently. You can make the beginning normal speed, the middle slow, and the end normal again. This works with any video, but it's most useful with Slo-Mo footage.

What if I recorded in Slo-Mo but want to play it at normal speed?

Open the video in Photos, tap Edit, and drag the speed slider all the way to the right to 2x. This plays the Slo-Mo video at double speed, which brings it back to roughly normal playback. Save it as a new clip if you want to keep both versions.