Upload the video file, pick a speed factor (0.25x to 4x), and download - the audio track's pitch and duration are kept matched to the new video timing, not just sped up or slowed down separately.
Video Speed Changer
Speed up or slow down a video, right in the browser.
Key features
- Upload the video file, pick a speed factor from 0.25x to 4x, and download the result.
- The audio track's pitch and duration stay matched to the new video timing, instead of the sound playing at a mismatched speed.
How changing speed affects the file
Changing speed re-encodes the video (unlike trim or strip-audio, which copy the stream losslessly), so it takes longer than a simple cut and the output is not byte-identical to the source.
Your files stay in the browser
The video is re-timed entirely inside this browser tab, so the clip you drop in never leaves your device for a server.
Related video tools
To trim, compress, or remove the audio from the video instead, see the related tools below.
Why the video and audio stay in sync at every preset
The video track is re-timed by rewriting each frame's presentation timestamp, so a 2x speed pick shrinks the timing by half and a 0.5x pick doubles it, while the audio is stretched with a separate tempo filter that preserves pitch rather than raising or lowering it. That tempo filter only accepts a factor between 0.5x and 2x per pass, so the extreme presets in the "Speed:" menu are done in stages and still land at the exact duration of the sped-up video. Because both streams are re-computed rather than copied, the result is never byte-identical to your upload - the tradeoff for keeping speech and music intelligible instead of chipmunked or droning.
| Speed you pick | How the audio is kept in step |
|---|---|
| 0.5x to 2x | one tempo pass, pitch preserved |
| 3x or 4x | two tempo passes chained (for 4x, 2x then 2x) |
| 0.25x | two half-speed passes chained |
The menu is deliberately limited to fixed steps (0.25x, 0.5x, 0.75x, 1.25x, 1.5x, 2x, 3x, 4x) rather than an arbitrary slider, so you always know the exact multiplier being applied. All of this runs single-threaded in the browser tab, meaning a short 1080p clip finishes in seconds while a long 4K source can take several minutes and is bound by your own device's processor, not a remote server.
Frequently Asked Questions
What does Video Speed Changer do?
Speed up or slow down a video, right in the browser.
When should I reach for video speed changer?
Changing speed re-encodes the video (unlike trim or strip-audio, which copy the stream losslessly), so it takes longer than a simple cut and the output is not byte-identical to the source.
What complementary tools work well alongside video speed changer?
To trim, compress, or remove the audio from the video instead, see the related-tools section.