How to Make a Slow-Motion Video from Any Clip

To make a slow-motion video, open Change Video Speed, add the clip, pick 0.5× · slow motion (or 0.75× for a gentle slow-down, 0.25× · very slow for extreme), and press Change speed. Download the MP4. For the smoothest result, start with a short clip filmed at 60 frames per second or more.

Slow a video down step by step

1. Cut the moment first. Slow motion works on a few seconds — the jump, the splash, the goal. Trim it with the Video Cutter.
2. Open Change Video Speed and add the clip.
3. Choose the Speed: 0.75×, 0.5× · slow motion or 0.25× · very slow. The new length is shown, such as "0:04 at 0.5× = 0:08".
4. Choose the Sound: keep it (it slows down at the same pitch) or remove it.
5. Press Change speed to … and download the MP4.

Why frame rate matters

A normal video has 24–30 frames per second. Slowing it to 0.5× shows each frame twice as long — only 12–15 new pictures each second — so movement looks a bit stepped. Footage filmed at 60 fps slowed to 0.5× still has 30 new frames a second and looks perfectly smooth.

The tool doesn't invent new in-between frames; it shows the existing ones for longer. So:

• 30 fps footage: 0.75× looks smooth; 0.5× is fine for most uses.
• 60 fps footage: 0.5× looks smooth; 0.25× is acceptable.
• 120–240 fps slo-mo footage: already slow motion on your phone — see below.

Filming for slow motion

• Use 60 fps in your camera settings (Settings › Camera › Record Video on iPhone; the video settings in Android camera apps).
• Or use the Slo-mo mode on your phone, which records at 120 or 240 fps.
• Good light helps — high frame rates need more light to stay sharp.
• Hold steady — slow motion exaggerates shake.

Phone "Slo-mo" videos that play at normal speed

iPhone Slo-mo clips are stored at 120 or 240 fps with a note telling Photos which part to play slowly. Elsewhere — on a computer or after uploading — they often play at normal speed. To fix that permanently, slow the clip with this tool to 0.25× (for 120 fps footage, 0.25× gives 30 new frames per second — perfectly smooth).

Sound in slow motion

Slowed speech sounds drawn out. For action moments, remove the sound and add music or a sound effect with Add Audio to Video — the classic sports-replay feel.

Creative combinations

• Slow, then reverse: a slowed-down splash played backwards with Reverse Video looks magical.
• Normal–slow–normal: split the clip into three with the Video Splitter, slow the middle part, and join them with the Video Merger.

How long should a slow-motion clip be?

Short. A 2-second moment at 0.25× already lasts 8 seconds — plenty for a replay. Slow motion works best on a single action with a clear start and end: a jump, a throw, a splash, a hair flick. Trim tightly around it, so the slow part starts just before the action and ends just after.

Privacy

Everything runs in your browser using ffmpeg (WebAssembly); nothing is uploaded, and there's no watermark. The result is an MP4 (H.264 and AAC) that plays everywhere.

Frequently asked questions

What's the slowest speed?

0.25×, a quarter of normal speed. For slower, run the result through again.

Does slow motion make the file bigger?

Yes — the video becomes longer, so expect roughly twice the size at 0.5×.

Can I slow down just one part?

Yes: split out that part, slow it, and merge the pieces back together, as described above.