UseTool

Change video speed

Make a clip faster or slower, from quarter speed to four times. The sound follows along so picture and audio stay together.

Drop your video hereMP4 · MOV · WebM

🔒 Your videos never leave your device.

How it works

How it works

  1. 1

    Add what goes in

    Drop your MP4, MOV, M4V and WebM here, or pick it from your device.

  2. 2

    Start it

    Set the playback speed, then start. Everything runs in this browser — no upload, no queue, no account.

  3. 3

    Take the result

    The MP4 · WebM is ready the moment the run finishes. Save it straight to your device.

What this tool does

Change video speed
Speeds a clip up or slows it down, from a fast walkthrough to slow motion. The sound is stretched along with it and stays in sync; at extreme settings voices become hard to understand.

When you need this

  • A twenty-minute sunset recording should become a thirty-second time-lapse.
  • A fast sports move should be shown in slow motion for training.

Supported formats

MP4MOVWebM

Good to know

Frequently asked questions

What files can I use here?

Reads MP4, MOV, M4V and WebM. As many files at once as you like.

What do I get back?

You get MP4 · WebM.

Does the file lose quality?

Every frame is decoded and encoded again. That is what makes the file smaller or different — and it costs some detail, most visibly in fast motion and fine texture.

When does it not work?

Which video codecs work depends on your browser. Chrome and Edge read the most, including H.265 on many machines; Safari and Firefox refuse some. A file that will not open here usually opens in Chrome.

Does the video lose quality?

Only when it has to be re-encoded. Cutting, joining and removing the sound track copy the picture data unchanged, so those are lossless. Compressing and adding a watermark do re-encode, which is why they take longer.

How long may a video be?

There is no fixed limit. What decides is the memory of your device: a phone manages a few minutes comfortably, a computer handles far more. If a long video fails, splitting it first and working on the parts usually helps.

Private by design

Your files stay on your device

Your videos never leave your device.

Other tools

Ready-made

Workflows for this file type