Change Video Speed Online Free — Speed Up or Slow Down, Keep Pitch, Lossless, No Upload
Drop a video here
or click to choose (MP4, MOV, WebM, MKV…)
processed in your browser · never uploaded
Speed up or slow down a video in your browser. The picture isn't re-encoded, so it's instant and lossless. Nothing is uploaded.
A free online tool for making a lecture or meeting recording watchable at 1.5×, turning a clip into a 4× time-lapse, or checking a sports move in slow motion — no editor to install, nothing uploaded. Choose the speed with a slider (0.25×–4× in 0.05 steps) or a preset (0.5 / 0.75 / 1.25 / 1.5 / 2 / 3×); the preview plays at that speed so you can check the result first. The video stream is copied with rewritten frame timestamps only — no re-encoding, no quality loss, seconds even for long files. For audio, keep pitch stretches the sound without changing voice pitch (WSOLA), so 2× speech stays intelligible; turn it off and the pitch rises or falls with the speed like classic fast-forward or slow-mo. Output is an MP4 carrying the original video codec (WebM if the codec can't go in MP4), playable on iPhone, PC and every social platform. The key difference from typical online tools: your video never leaves your device. Everything runs locally via WebCodecs, so there is no upload wait, size cap or watermark. A recent Chrome or Edge is recommended.
How to use
- Drop in a video file (MP4, MOV, WebM…).
- Pick a speed with the slider or a preset (the preview plays at that speed). Leave keep pitch on if voices should sound natural.
- Press “Apply & save”, then download the video.
FAQ
Is my video uploaded?
No. Loading, changing the speed and exporting all happen inside your browser on your device — nothing is sent to or stored on a server. That's why there is no upload wait and no size limit.
Does it lower the video quality?
Not the picture. Frames are copied as-is with new display times, without re-encoding. Only the audio is re-encoded (AAC/Opus) because it has to be stretched.
Keep pitch on or off?
On for anything you want to understand — lectures, meetings, narration — since voices keep their natural pitch even at 2×. Off when you want the fast-forward or slow-mo effect, or want music's tempo and pitch to change together; then the pitch scales with the speed.
How fast or slow can it go?
From 0.25× (four times slower) to 4×. At extreme speeds the pitch-preserving stretch can add slight artifacts to the audio. Video uses the original frames only, so slow motion keeps the original frame rate with longer gaps — no new frames are interpolated.
Which formats are supported, and what is the output?
Input: MP4, MOV, WebM, MKV and other formats your browser can read. Output: MP4 with the original video codec copied in (WebM when the codec can't be stored in MP4), with AAC audio (Opus for WebM). Processing uses WebCodecs, so a recent Chrome or Edge is recommended.