Use the free Video Speed Changer below: your video never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
What the Video Speed Changer does
Sometimes a video is too slow to watch, or too fast to follow. A long lecture drags. A short clip flashes past before you can see what happened. The Video Speed Changer fixes that by recording a new copy of your video at a different speed. You can slow a clip to half speed, or speed it up to one and a half times or double speed.
The new copy is a real video file that you can download, share, or upload anywhere.
Everything runs in your browser. There is no account to create, no software to install, and no upload. Your video stays on your own device from start to finish.
How to use it
First, choose a video file from your device. MP4 and WebM files work best, because browsers can play them directly. A short preview appears so you can check you picked the right clip.
Next, pick a speed. Choose 0.5x to slow the video down to half speed. Choose 1.5x to make it fifty percent faster. Choose 2x to play it at double speed. If you only want the pictures and not the sound, tick the “Mute audio” box.
Then press “Change speed” and wait. Processing takes about the length of the clip, so a two-minute video takes about two minutes at normal recording speed, and less at faster speeds. Keep the tab open while it works.
When it finishes, you see the original duration next to the new duration, and a preview player for the new video. Press the download link to save it. If the speed is not right, try again with a different speed.
Worked example
Here is a real test with this tool. The starting clip was 2.0 seconds long, 320 by 240 pixels, and 31.9 KB in size. It was a short test clip with a tone sound track.
With the speed set to 1.5x, the tool recorded a new video of 1.3 seconds. That matches the maths: 2.0 divided by 1.5 is 1.33 seconds. The new file was 89.1 KB in MP4 format.
Notice that the new file is bigger than the original, even though it is shorter. That is because the tool re-encodes at a fixed recording quality, and the tiny original was very heavily compressed. Speed changing is not a way to shrink a file. If you also need a smaller file, use a video compressor after changing the speed.
When a speed change helps
Speeding up is useful for lectures, meetings, and screen recordings where someone talks slowly. At 1.5x you can get through the same material in a third less time, and most speech is still easy to follow.
Slowing down helps when you need to study movement: a sports technique, a dance step, a craft skill, or a repair job. At 0.5x you can see details that flash past at normal speed.
Creators also use speed changes for effect. A fast version of a long process looks like a time-lapse, and a slow version of a quick moment feels dramatic. You can drop the output straight into an editor or upload it.
Honest limitations
The output is re-encoded, not a lossless copy. Re-encoding can soften fine detail slightly, especially in a video that was already heavily compressed. The tool cannot improve the quality of the original.
Audio pitch shifts with speed. That is how this kind of speed change works: faster audio sounds higher, and slower audio sounds lower. If the shifted voice bothers you, mute the audio and keep only the pictures.
The output format depends on your browser, and the tool tells you the format before you start. Chrome, Edge, and recent Safari record MP4. Firefox records WebM only. A WebM file plays in Chrome, Firefox, and Edge, but older Safari versions may not play it.
Processing happens in real time, so a long video takes a long time. Very large files can also strain a weak device. For best results, use short clips, and close other heavy tabs while the tool works.
Frequently asked questions
Does the tool upload my video anywhere? No. The file is read on your device, drawn through the browser, and recorded back on your device. Nothing is sent to a server.
Why does the voice sound strange after speeding up? Because the audio is sped up along with the picture, its pitch rises. This tool does not preserve pitch. If you need natural-sounding speech, mute the audio or keep the speed change small.
What format will my new video be? The tool checks your browser first and shows the answer before you start. Most Chrome, Edge, and Safari users get MP4. Firefox users get WebM.
How long does it take? About the length of the new clip. A 2-second clip at 1.5x takes just over a second of recording, plus a short start-up pause. A 10-minute clip at 2x takes about 5 minutes to record, while the same clip at 0.5x takes about 20 minutes, because slow motion plays for longer.