Change the speed of a video
Drop a video and pick a speed: 0.5× for slow motion, 1.5× for a talk, 2× for a time-lapse. The sound follows, with its pitch kept so voices sound natural, or like a sped-up tape if you prefer.
Updated October 30, 2026
Options
How it works
- Drop a video anywhere on this page.
- Pick a speed (or type one from 0.25 to 4) and choose whether voices keep their pitch.
- Download the video (longer clips: press Change video speed first); its length follows the speed.
Typical uses, and the speed that fits
A time-lapse of a sunset or a drawing works at 2× to 4×. A tutorial that drags reads well at 1.25× or 1.5× with the voice kept at its pitch. A sports move or a jump looks best as slow motion at 0.5× or 0.25×, especially when the camera recorded 60 frames per second or more. The default is 2×; type any value from 0.25 to 4 for something in between.
The result's length is shown under the options before you start, so a 10-minute screen recording at 1.5× is announced as the 6 minutes 40 it will become.
Smooth or Lossless, in practice
Smooth is the safe choice for anything you will share: the frame rate stays the same, the file plays everywhere, and the picture is re-encoded at a bitrate that follows the source. Lossless skips the re-encoding and simply re-times every frame, which is quick and loses nothing, but the frame rate moves with the speed. A 30 fps clip at 4× becomes 120 fps, which some phones and sites refuse; at 0.25× it drops to 7.5 fps and looks like a slideshow. Use Lossless for a desktop player or for a clip you will process again.
Size, time and phones
A sped-up clip is shorter, so it is usually smaller; a slowed-down one is longer and larger. Up to 5 videos of up to 2 GB can take the same speed in one list. The encoding runs in your browser on your own processor, so the video never leaves your device; a long 4K clip takes a while, and on a phone it is better to keep the page in front while it works.
Why people use it
Free, no account
Every tool is free, with no sign-up, no e-mail address and no limit on how often you use it.
Your files stay on your device
The browser opens the file and processes it in memory, on your device. Nothing is uploaded, so nothing can be kept, leaked or looked at.
No watermark
The result is yours as it is: no watermark, no branding, no trial version.
Any device
A phone, a tablet or a computer with a current browser is enough: no app to install, no software to update.
Works offline after the first visit
The browser keeps the pages and their engines, so a tool you have opened once keeps working without a connection.
Open-source engines
The code that does the work is open-source software, named on the Licences page, running as WebAssembly in your browser.
Why it is private
Everything you type or drop here is handled by your browser, on your device. Nothing is uploaded. To verify, open your browser's developer tools, go to the Network tab, and use the tool: you will see no request carrying your data.
While a file is being processed, the counter under the result shows the page's network traffic: 0 requests and 0 B for your data.
How to check it yourself, step by step
What you can check yourself
Open your browser's developer tools on the Network tab before you drop a file: while the tool works you will see no request carrying your data, and the counter under every result shows the page's own measurement.
The site sets no cookies, so there is no cookie banner. Anonymous usage counts and error reports without file names are the only things that leave the page, as the privacy policy describes.
Every change goes through thousands of automated tests in three browser engines, including a guard that fails a test if a single byte of a file leaves the page.
Frequently asked questions
- Will voices sound like chipmunks?
- Not with “Keep the pitch of voices” on (the default): the sound is time-stretched, so it gets faster or slower at the same pitch. Turn it off for the classic effect: the sound is resampled like a tape, higher when sped up and lower when slowed down.
- Smooth or lossless?
- Smooth keeps the frame rate: sped up, frames are skipped; slowed down, frames are shown twice; the video is re-encoded and plays everywhere. Lossless keeps every frame and only changes its timing, so the video is copied quickly and without loss, but the frame rate changes with the speed (30 fps at 2× becomes 60 fps, at 0.5× 15 fps, which looks choppy).
- Can I speed up only part of the clip?
- Not yet: this tool changes the speed of the whole clip. For one part, cut that part out first, change its speed here, and join the pieces again.
- Is the slow motion smooth?
- It shows the frames the camera recorded for longer; it does not invent frames between them. Clips filmed at 60 fps or more look best slowed down.
- Which formats work?
- MP4, MOV, M4V, WebM and MKV; the result keeps the original's format (MOV and M4V become MP4). Re-encoding uses your browser's own encoders (WebCodecs), in current Chrome, Edge, Firefox and Safari. Nothing is uploaded.
- Can I change the speed of a video on my phone without an app?
- Yes, in the phone's browser. Short clips are quick; a long 4K recording may be more than a phone's memory can hold, and the tool says so before it starts.
- Can I remove the sound at the same time?
- Not in this tool. Change the speed first, then send the result to Change video volume and choose Remove the sound; the picture is copied there without being re-encoded again.
- Does the file get smaller or bigger?
- It follows the new length: at 2× the clip is half as long and roughly half the size; at 0.5× it is twice as long and larger. The bitrate of a Smooth result follows the source's own.
- Can I change the speed of several videos at once?
- Yes, up to 5 in one list, all at the same speed and with the same frame and pitch settings. Each result is downloaded separately.
- Does it work on a video with no sound?
- Yes. The picture is sped up or slowed down as usual and the pitch setting simply has nothing to apply to.
Install it as an app
Chrome, Edge and Android browsers offer to install this site from the address bar or the menu; on iPhone use Share, then Add to Home Screen. It opens like an app, keeps working offline and still processes everything on your device.