Change video speed
Drop an MP4, pick a playback speed, and download the result. The first time you use this tool the video engine downloads once (~26 MB); after that the browser uses its cached copy. Your file never leaves your device.
About changing video speed
Changing the playback speed re-encodes the video so it plays faster or slower without changing the pitch of the audio. At 0.5× the video plays at half speed (slow-motion); at 2× it plays twice as fast; at 4× four times as fast. The audio tempo is adjusted to match — the pitch stays the same, only the pace changes.
The operation requires a full re-encode, so it takes longer than a simple trim or container conversion. For videos without an audio track the audio step is skipped automatically. Output is H.264 MP4 at ffmpeg's default quality.
Is it private?
Yes. The speed changer is WebAssembly and browser APIs running on your own machine. Nothing is uploaded, stored, or seen by us — there is no server to send files to.
Frequently asked questions
- Does changing the speed affect the audio pitch?
- No. The audio tempo is adjusted to match the new pace, but the pitch stays the same. At 0.5× the video plays at half speed and at 2× it plays twice as fast, while voices keep their normal tone.
- Are my files uploaded to a server?
- No. The speed changer runs on your device using WebAssembly and browser APIs. Your video is never sent anywhere, and the tool keeps working even if you go offline after the page loads.
- Is it free, and do I need an account?
- It is free with no watermarks, no daily caps, and no sign-up. Drop a file, pick a speed, and download the result.
- Why does it take a while, and what about the file size?
- Changing the speed requires a full re-encode, so it takes longer than a simple trim or container conversion. The output is H.264 MP4 at ffmpeg's default quality. The first time you use the tool the video engine downloads once (~26 MB), then the browser uses its cached copy.