Video Speed Changer
Speed up or slow down a video right in your browser — preview any rate from 0.25× to 4× and export a new file with the audio in sync.
Drag & drop a video here, or click to browse
MP4, WebM, MOV or any clip your browser plays. No uploads — it stays on your device.
0.25× to 4× — below 1× is slow motion, above 1× is fast forward.
Result
How it works
Drop in a clip and it is read straight from disk with the File API — nothing is uploaded, so private recordings, lectures and phone videos never leave your device. Moving the slider (or tapping a preset) sets the playback rate of the preview immediately, anywhere between 0.25× slow motion and 4× fast forward, so you can judge the speed before you commit to a file.
Export video then plays the clip at that rate while the picture is captured from a canvas and the sound is taken from the video element, and the pair is written into a new WebM file with the browser's built-in MediaRecorder — no ffmpeg, no server, no watermark. Because it re-records in real time, a 2× export takes half the length of the clip and a 0.5× slow-motion export takes twice as long; leave the tab in the foreground while it runs. WebM plays in Chrome, Edge, Firefox and most editors; if you need MP4, import the WebM into your editor of choice.
Frequently asked questions
How do I change the speed of a video?
Drop your MP4, WebM or MOV clip onto the box above and drag the speed slider — or tap a preset such as 0.5× or 2×. The preview changes rate immediately and the tool shows how long the result will be, so you can judge it before rendering. When you are happy, press Export video: the clip is replayed at that rate and re-recorded into a new WebM file you can play, download or describe with the Copy details button.
Is this video speed changer free, and does it watermark my video?
It is completely free, there is no sign-up and nothing is ever stamped on the picture. The whole job runs as JavaScript inside this page using the browser's Canvas and MediaRecorder APIs, so your video is never uploaded to a server, there is no queue or file-size tier, and no copy of your clip is left anywhere to expire later.
Does speeding up a video lose quality, and what happens to the audio?
The frames are captured at the original size (up to 1280 px wide) and re-encoded to WebM, so the picture is re-compressed once — visually very close to the source, though not a bit-for-bit copy. The audio is captured alongside it and speeds up with the picture, so it stays in sync but rises or drops in pitch; untick the audio option if you would rather export a silent clip. Exporting runs in real time, so a 2× export takes half the length of the clip and a 0.5× slow-motion export takes twice as long.