Change video speed

How it works

1. 1

   Add your video

   Drop in the video you want to run faster or slower.

2. 2

   Pick a speed

   Choose anywhere from 0.25x (slow motion) to 4x (fast forward).

3. 3

   Download

   Save the retimed video with audio kept in tune. No watermark.

What actually happens when you speed a video up or slow it down

Speeding up is the easy direction. A video played at twice the rate needs half as many frames, so frames are dropped or blended together, and because the eye is being given less time to inspect each one, the loss is essentially invisible. Fast motion hides everything.

Slowing down is the direction that disappoints people, and the reason is arithmetic. A clip shot at 30 frames per second and played at half speed still only has 30 real frames for every two seconds it now occupies, so each one has to be held on screen twice as long. That is what produces the judder people describe as looking cheap. Genuine slow motion is a property of the recording, not the edit: it needs footage captured at a high frame rate in the first place, which is exactly what your phone's slow motion mode is doing when it records at 120 or 240 frames per second.

Audio has its own problem. Play a soundtrack faster and every frequency in it rises with the speed, which is why a naive speed change turns voices into chipmunks. Preserving the pitch means stretching the audio in time while leaving its frequencies alone, a genuinely separate operation from the one being performed on the picture, and the reason speed changes cost more processing than they look like they should.

Change video speed in the browser, with no upload

Speed ramps from a slow crawl to several times normal, applied on your own device, with no upload and no watermark on the result. There is no cap on the length of the source, so a long lecture can be taken to 1.5x and downloaded as a shorter file rather than merely played faster in a player.

Because nothing is uploaded, trying 1.5x, listening, and settling on 1.25x costs only the encode. That is the honest way to choose a speed for speech, where the right answer depends entirely on how quickly the person was already talking.

If the aim is a shorter file rather than a faster one, trimming the dead sections is the better tool and costs no quality at all.

Why nothing uploads

Other tools send your video to their servers, which costs them money per file, so they add watermarks, cap file sizes, and make you sign up. This tool does the work right here in your browser using your own device. Your file is never uploaded, so there is no wait, no watermark, no size limit, and no account.

Questions

Does the audio stay in sync?

Yes. The audio is retimed to match and kept at its normal pitch so it does not sound chipmunky.

Can I make slow motion?

Yes. Pick 0.5x or 0.25x to slow the video down.

Does my video get uploaded?

No. The speed change happens in your browser; your file never leaves your device.

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