Free Online Video Speed Changer
Speed up or slow down a video from 0.25x to 4x.
Turn this off for a chipmunk or slow-monster voice effect.
Exporting plays the clip once through a canvas and audio graph, so a 10× slower clip takes about 10× longer than the source to record.
Speed-changed video
ReadyAbout the Video Speed Changer
Speeding up a clip is a simple way to make a slow tutorial watchable, turn a long timelapse into a few seconds, or fit a demonstration inside a short social post. Slowing it down reveals motion that happens too quickly for the eye, such as a golf swing, a chemical reaction, or a bird taking off. This tool changes the playback speed of any browser-playable video from 0.25× to 4× and exports a new file that already reflects that speed.
Preview and pitch
Moving the slider immediately changes how the preview plays, so you can judge whether a scene feels rushed or too slow before committing. With Preserve the original pitch enabled, the tool asks the browser to keep voices and music at their natural register while the timing changes. Disable it to let the pitch rise with faster speeds and fall with slower ones, which is the classic tape-style effect.
How the export works
The clip is played at the chosen rate. Each frame is painted onto a canvas, and the audio is routed through the Web Audio API, so the recorded result has both the new timing and the matching soundtrack. Output length is the source duration divided by the speed: a one-minute clip at 2× becomes about thirty seconds, while 0.5× produces roughly two minutes. Because the recording happens in real time, slow speeds take proportionally longer to export than fast ones.
Quality and format
Re-encoding is unavoidable with this browser-only method. The picture keeps its original resolution, but a
second pass through the encoder can soften fine detail. Fast motion may also show more compression than a
desktop editor would produce. When MP4 with H.264 is available, the download is an .mp4 file;
otherwise the tool records WebM and labels the actual format in the result card.
Frequently asked questions
Does the audio speed up too?
Yes. The audio is captured through the Web Audio API at the same playback rate as the picture, so the soundtrack stays in sync with the new speed.
Can I make a smooth slow-motion clip?
This tool slows playback, but it cannot invent frames that were never recorded. At 0.25× the same frames are shown for longer, so very fast action may look choppy rather than smoothly slowed.
Why does the exported duration differ slightly?
The encoder needs a fraction of a second to start and flush, and playback timing is not frame-exact. Expect a small difference rather than an exact mathematical result.