Video & Audio
Change Video Speed
Make a video faster or slower, with voices kept at their own pitch. No upload, no signup.
Files stay on your device How it works
Drop a file here, paste, or
MP4, MOV, WebM or MKV · one file, up to 25 MB
Your files
Your file is ready
How to speed up or slow down a video
Speeding up suits a long screen recording or a walk-through; slowing down suits a moment you want to see more clearly.
- Choose a video, MP4, M4V, MOV, WebM or MKV, up to 25 MB and 30 minutes long. A line under it shows its length, picture size and formats.
- Pick a speed, from 0.25× to 4×, and whether to keep the sound. The result can be up to 30 minutes long.
- Press Change speed and download the copy: clip.mp4 at 2× becomes clip-2x.mp4.
The picture: copied, not re-encoded
Every frame is kept as it was, and only its timing changes, so it’s quick and nothing is lost. The length changes in step: a 10-minute video at 2× lasts 5 minutes. A faster video plays more frames a second: a 30-frames-a-second video at 2× plays 60. A slower one shows each frame for longer, and no frames are invented, so slow motion looks smooth only from video filmed at a high frame rate. The note under the result gives the new length and frame rate.
The sound: same pitch
Played faster, a recording normally sounds higher, and slower, lower. Here the sound is decoded and time-stretched instead, by a method called WSOLA: it’s cut into short overlapping pieces, each nudged so the waves line up, then laid down closer together or further apart. Voices keep their pitch. Speech stays natural; music with sharp beats can smear at large changes. The sound is then re-encoded: AAC in MP4 and MOV files, Opus in WebM and MKV. Firefox can’t make AAC, so there an MP4 or MOV gets Opus sound, which browsers and VLC play.
Which browsers work
Removing the sound needs nothing special, because the picture is only copied: it works in current Chrome, Edge, Firefox and Safari, even with HEVC (H.265) video from an iPhone. Keeping the sound means making it anew, which needs a current Chrome, Edge or Firefox, or Safari 26 or later.
Good to know
Your video stays on your device; nothing is uploaded. The copy keeps the original’s format, picture size and rotation; an M4V comes out as an MP4. This tool keeps every moment and changes how fast it plays; to cut parts out instead, use Trim Video, then change the speed of the part you kept.