Video Speed Changer — Speed Up or Slow Down, Free

Speed a clip up or slow it down without chipmunk voices

Faster playback turns a long recording into a quick time-lapse, and slower playback lets you study a movement or add drama. This tool changes the speed from 0.25x to 4x, adjusts the sound so the pitch stays natural instead of squeaking or growling, and gives you a new MP4. It runs on your device and nothing is uploaded.

How the new length works out

The new length is the old length divided by the speed. A 60 second clip at 2x lasts 30 seconds, at 4x it lasts 15, at 0.5x it lasts 120, and at 0.25x it lasts 240. A 90 second clip at 1.5x lasts 60 seconds. Pick the speed that gets you to the length you need.

What happens to the sound

Simply playing audio faster raises its pitch and slower lowers it. This tool changes the tempo of the sound without changing its pitch, so speech stays recognisable at 1.5x and 2x. At 3x and 4x speech becomes hard to follow however it is processed, so for extreme speeds you may prefer to remove the audio with the checkbox.

Smooth speed-ups, choppy slow motion

Speeding up works by dropping frames, which looks smooth. Slowing down works by showing frames for longer, and slowing a clip down does not invent new frames, so deep slow motion on footage filmed at an ordinary frame rate looks steppy. For the smoothest slow motion, film at a high frame rate to begin with.

Pair it with the other tools

Cut the part that matters with the video trimmer before changing its speed, repeat the result with loop video, or turn a short sped-up moment into a GIF.

Frequently asked questions

How do I speed up a video?

Drop the video into the box, choose a speed such as 2x and press Change speed. The tool makes a new MP4 that plays at that speed, with the sound kept at a natural pitch, and you download it.

How do I make a video slow motion?

Choose a speed below 1x, such as 0.5x, which doubles the length. Slowing down repeats frames rather than creating new ones, so it looks smoothest on footage that was filmed at a high frame rate.

How long will the video be after I change the speed?

The new length is the old length divided by the speed. A 60 second video lasts 30 seconds at 2x, 15 seconds at 4x, 120 seconds at 0.5x and 240 seconds at 0.25x.

Will the voices sound like chipmunks when I speed it up?

No. The tool changes the tempo of the audio and keeps its pitch, so speech sounds natural at moderate speeds. At 3x and 4x speech is hard to follow regardless, and you can tick the box to remove the audio instead.

What speeds can I choose?

0.25x, 0.5x, 0.75x, 1.25x, 1.5x, 2x, 3x and 4x. For more than 4x, run the finished clip through the tool a second time.

Why does my slow motion look choppy?

Slowing a clip down shows each frame for longer instead of creating new frames in between, so footage filmed at an ordinary frame rate looks steppy when slowed far. Filming at a higher frame rate in the first place is the real fix.

Does changing the speed lower the quality?

The video is re-encoded once at a high quality setting, which is hard to see by eye. The resolution does not change.

Is my video uploaded, and is it free?

Nothing is uploaded. The speed change runs in your browser with a WebAssembly build of FFmpeg, and only the engine is downloaded the first time. It is free, with no watermark, no account and no limit on how many clips you change.