Speed up a video
Make a long recording quicker to watch, or turn it into a timelapse, without uploading it.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Speed up a video in your browser, 1.25× to 8×, with sound that keeps its pitch. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
A tutorial that drags, a screen recording with long pauses, a sunset that took twenty minutes: speeding the video up makes it watchable. Pick 1.25× or 1.5× to tighten a talk while keeping it natural, 2× to halve the length, or 4× and 8× for a timelapse.
Every frame is re-timed and the video is encoded again in your browser. The sound is sped up too, but keeps its pitch, so people still sound like themselves; tick Remove the sound if you would rather add music later.
Your video is not uploaded to a website, there is no watermark and no length limit, and you can speed up several videos in one go.
What happens to the frames depends on how far you go. A 30 fps phone clip at 2× plays 60 frames a second and keeps every one of them. Beyond that, frames faster than 60 a second are dropped, since screens cannot show more: at 4× only every other frame of a 30 fps clip is kept, and at 8× one in four. That keeps the file from ballooning, and it is also why fast movement can look a little jumpy at 8×, while slow subjects such as clouds, shadows or a drawing in progress look smooth.
For a long screen recording, such as a 40 minute coding session or a software setup, 8× turns it into a 5 minute summary and 4× into a 10 minute one. At those speeds speech is too quick to follow even at its normal pitch, so tick Remove the sound and put a voice-over or music on it later with Add audio to video. For a lecture or a meeting you still want to listen to, stay at 1.25× or 1.5×, where voices remain easy to understand.
How it works
- Drop one or more videos.
- Choose how much faster (2× is selected).
- Press Change speed and save the MP4s.
In your browser, not on a server
Mediabunny (MPL-2.0) decodes the video in your tab and gives every frame a new time; when speeding up, frames beyond 60 a second are dropped. The sound track is decoded by your browser and stretched with WSOLA, a method that overlaps short slices of sound so the pitch stays the same. Both are encoded again by your browser (WebCodecs) into an MP4, H.264 and AAC where available.
Compared with upload-based tools: Online speed changers upload the video to process it, cap free files, and often add a watermark or turn voices into chipmunks. Here the video stays on your device and the sound keeps its pitch.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
How much faster should I go?
1.25× to 1.5× keeps speech easy to follow. 2× is the usual “fast forward”. 4× to 8× suits timelapses of drawing, cooking or clouds.
Can I speed up a video more than 8×?
The menu stops at 8×, but you can run the result through the page again. 8× twice is 64×, which turns an hour of clouds, traffic or a 3D print into under a minute. Each pass encodes the video again, so expect a little loss of detail on the second pass. The file name gains a speed tag each time, such as -8x.
Can I use this to fit a clip into a time limit?
Yes. Divide the clip's length by the limit to find the speed you need: a 90 second clip needs 1.5× to fit in 60 seconds, and a 2 minute clip needs 2×. The choices are 1.25×, 1.5×, 2×, 3×, 4× and 8×, so pick the first one that brings it under the limit, then trim any spare seconds with Trim video.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after one visit to save itself for offline use; then you can turn off Wi-Fi and it still works.
More video and audio tools
Change video speed
Make a video faster or slower, with sound that stays at the right pitch. Done on this device, never uploaded.
Add audio to video
Put music or a voice-over on a video, or replace its sound. The picture is copied as it is, and nothing is uploaded.
Reverse video
Make a clip play backwards, for a rewind effect, a boomerang or a laugh. Done on this device, never uploaded.
Video to JPG
Turn a video into still images: a few good frames or every single one. Done on this device, never uploaded.
Other conversions
Guides
- How to slow down or speed up a videoThis changes the saved file itself, not just how a player plays it back. Here is what actually works, including keeping the audio in tune.
- How to reverse a videoRewind effects are popular, but most phones have no reverse button. Here is where it exists, and a way to do it without installing an app.