Click to upload or drop a video to slow down
MP4, MOV, WebM or MKV — slowed down in your browser, never uploadedVideo and audio are processed in your browser by FFmpeg (ffmpeg.wasm), free software under the GPL-2.0-or-later and MIT licenses — licenses & source.
About the slow motion video maker
This free tool turns any clip into a slow motion video. Choose 0.75x, 0.5x (half speed) or 0.25x (quarter speed), watch the preview at that speed, and press Make slow motion video. You get an MP4 you can download and share.
You can keep the sound — it is slowed down too, but stays at its own pitch, so a voice does not drop into a deep growl — or remove it, which is what most slow motion clips do.
Everything runs in your browser. Your video is never uploaded, and there is no watermark.
Features
- 0.75x, 0.5x and 0.25x presets, plus any custom speed from 0.1x
- Live preview at the chosen speed before you make the file
- New length shown before you start
- Sound at its own pitch, or no sound at all
- MP4, MOV, WebM, MKV in — MP4 out (H.264 and AAC)
- Private — no upload, no sign-up, no watermark
How long the slow motion video will be
Slowing down makes the video longer by the same factor. 0.5x is twice as long; 0.25x is four times as long.
| Original clip | 0.75x | 0.5x | 0.25x |
|---|---|---|---|
| 5 seconds | 6.7 s | 10 s | 20 s |
| 10 seconds | 13.3 s | 20 s | 40 s |
| 30 seconds | 40 s | 1:00 | 2:00 |
| 1 minute | 1:20 | 2:00 | 4:00 |
| 3 minutes | 4:00 | 6:00 | 12:00 |
Slow motion works best on short moments: a jump, a splash, a goal, a dance move, a dog catching a ball. A 5 to 10 second clip at 0.5x or 0.25x is the usual choice.
Smooth slow motion: the frame rate matters
A video is a fast row of still pictures (frames). This tool does not invent new pictures. It shows each one longer (the saved file repeats it, so the frame rate number stays the same). So the slow video has fewer new pictures per second than the original:
| Filmed at | 0.75x | 0.5x | 0.25x |
|---|---|---|---|
| 24 fps | 18 new pictures/s | 12 | 6 |
| 30 fps (most phones) | 22.5 | 15 | 7.5 |
| 60 fps | 45 | 30 | 15 |
| 120 fps | 90 | 60 | 30 |
| 240 fps | 180 | 120 | 60 |
Motion looks smooth from about 24–30 new pictures per second. So:
- A normal 30 fps phone video looks fine at 0.75x, a little choppy at 0.5x, and jumpy at 0.25x.
- A 60 fps video looks smooth at 0.5x.
- For smooth 0.25x, film at 120 or 240 fps. Many phones can do this in their slow-mo mode or in the camera's frame rate setting.
Tip: if your phone has a 60 fps setting, turn it on before you film something you want to slow down later.
The sound in slow motion
- Keep the sound — the sound is stretched to the new length, but the pitch is corrected, so voices keep their normal height. At 0.5x speech sounds slow but clear. At 0.25x it sounds drawn out and a little robotic.
- Remove the sound — the usual choice for sport and action clips. Add music later with Add Music to Video.
Frequently asked questions
How do I make a slow motion video?
Drop your clip on the box, choose 0.5x (or 0.25x), check the preview, and press Make slow motion video. When it is ready, play it and press Download. The first time, the page also loads its video engine (about 30 MB).
Why does my slow motion video look choppy?
The clip has too few frames for that speed. A 30 fps video at 0.25x shows only 7.5 new pictures per second. Choose 0.5x or 0.75x, or film the moment again at 60, 120 or 240 fps.
Can I slow down only part of a video?
The whole file is slowed. Cut out the moment first with Trim Video, slow it down here, and join it with the rest using Merge Video.
Does the voice sound deep in slow motion?
No. The tool corrects the pitch, so the voice stays at its normal height — only slower. The deep "movie slow-mo" voice needs sound that is slowed without that correction, and this tool does not do that.
How long does it take?
The video is re-encoded in your browser. A 10-second clip takes a few seconds to a minute; slowing it down makes the new file longer, so it takes a little longer than the original clip would.
Is my video uploaded?
No. The video is processed inside your browser with ffmpeg. It never leaves your device.
Related tools
- Speed Up Video — the other way: 1.5x, 2x or 4x faster
- Change Video Speed — every speed from 0.25x to 4x on one page
- Reverse Video — play the moment backwards
- Loop Video — repeat the slow motion clip
- MP4 to GIF — turn the moment into a GIF
How to use it
- Drop your video on the box, or click to choose a file
- Pick a speed — 0.75x, 0.5x or 0.25x — or type your own
- Watch the preview; it plays at that speed
- Choose to keep or remove the sound
- Press Make slow motion video, wait, then Download
