How to Speed Up or Slow Down a Video Online (0.25x to 4x)

Why Change a Video's Speed?

Changing the playback speed is one of the simplest edits, and one of the most effective:

Speed up a long tutorial, a screen recording or a cooking video so viewers don't get bored.
Turn a sunset, a construction site or a drawing session into a timelapse.
Slow down a sports move, a splash or a jump to show what the eye can't see.
Shorten a video to fit a duration limit (stories, reels, a presentation slot).
Make a short, punchy GIF from a long demo.

Change the Speed in 3 Steps

The video speed tool uses FFmpeg compiled to WebAssembly: everything happens in your browser, and the video is never uploaded.

Change video speed

Slow motion or fast forward, from 0.25x to 4x, audio kept.

Try it for free

Import your video — MP4, MOV, AVI, MKV or WebM, up to 100 MB.
Choose the speed with the presets or the slider, from 0.25x (4 times slower) to 4x (4 times faster).
Choose what happens to the sound: keep it at the new speed, or remove it — then download.

What Happens to the Audio?

When you speed up a recording naively, voices go up in pitch — the famous "chipmunk effect". Our tool preserves the pitch: the audio follows the new speed, but voices stay natural. For a 1.25x or 1.5x tutorial, that's exactly what you want.

At extreme speeds (0.25x or 4x), speech becomes hard to follow anyway. In that case, removing the sound and adding music afterwards often gives a better result.

Which Speed for Which Use?

Goal	Speed	Sound
More dynamic tutorial or presentation	1.25x – 1.5x	Keep
Screen recording, software demo	1.5x – 2x	Keep or remove
Timelapse (sky, crowd, drawing)	3x – 4x	Remove
Light slow motion (sport, dance)	0.5x	Remove or keep
Strong slow motion (splash, impact)	0.25x	Remove

Need more than 4x?

To make a real timelapse of a 1-hour recording, apply the tool twice: 4x then 4x again gives 16x. Each pass re-encodes the video, so start from the best quality possible.

Why Does My Slow Motion Look Choppy?

Slowing down a video doesn't create new frames: each frame is simply shown longer. A video filmed at 30 frames per second slowed down to 0.25x is displayed at the equivalent of about 7.5 frames per second — and that looks jerky.

For smooth slow motion, film in high frame rate from the start: most smartphones offer a "Slo-mo" mode at 120 or 240 fps. A 120 fps clip slowed down to 0.25x is still at 30 fps — perfectly smooth.

Combine with Other Tools

Trim first: keep only the useful passage with the video trimmer, then change its speed — faster and lighter.
Make a GIF: a sped-up demo converted with the video to GIF converter gives a short, shareable animation.
Compress afterwards: if the file is too heavy for WhatsApp or email, the video compressor has presets for each use.

Conclusion

Speeding up or slowing down a video takes a few seconds and can transform a boring clip into an engaging one. Choose 1.25x–2x for tutorials, 3x–4x for timelapses, and 0.5x or less for slow motion — ideally filmed at high frame rate. All without installing software or uploading your video.